diff --git a/packages/core/src/components/alert-dialog/alert-dialog-action.tsx b/packages/core/src/components/alert-dialog/alert-dialog-action.tsx
new file mode 100644
index 0000000..9553b41
--- /dev/null
+++ b/packages/core/src/components/alert-dialog/alert-dialog-action.tsx
@@ -0,0 +1,25 @@
+import type { JSX } from "solid-js";
+import { splitProps } from "solid-js";
+import { useInternalAlertDialogContext } from "./alert-dialog-context";
+
+/** Props for AlertDialog.Action. */
+export interface AlertDialogActionProps extends JSX.ButtonHTMLAttributes<HTMLButtonElement> {
+  children?: JSX.Element;
+}
+
+/** Confirms the action and closes the AlertDialog. */
+export function AlertDialogAction(props: AlertDialogActionProps): JSX.Element {
+  const [local, rest] = splitProps(props, ["children", "onClick"]);
+  const ctx = useInternalAlertDialogContext();
+
+  const handleClick: JSX.EventHandler<HTMLButtonElement, MouseEvent> = (e) => {
+    if (typeof local.onClick === "function") local.onClick(e);
+    ctx.setOpen(false);
+  };
+
+  return (
+    <button type="button" onClick={handleClick} {...rest}>
+      {local.children}
+    </button>
+  );
+}
diff --git a/packages/core/src/components/alert-dialog/alert-dialog-cancel.tsx b/packages/core/src/components/alert-dialog/alert-dialog-cancel.tsx
new file mode 100644
index 0000000..db50c08
--- /dev/null
+++ b/packages/core/src/components/alert-dialog/alert-dialog-cancel.tsx
@@ -0,0 +1,25 @@
+import type { JSX } from "solid-js";
+import { splitProps } from "solid-js";
+import { useInternalAlertDialogContext } from "./alert-dialog-context";
+
+/** Props for AlertDialog.Cancel. */
+export interface AlertDialogCancelProps extends JSX.ButtonHTMLAttributes<HTMLButtonElement> {
+  children?: JSX.Element;
+}
+
+/** Cancels the action and closes the AlertDialog. */
+export function AlertDialogCancel(props: AlertDialogCancelProps): JSX.Element {
+  const [local, rest] = splitProps(props, ["children", "onClick"]);
+  const ctx = useInternalAlertDialogContext();
+
+  const handleClick: JSX.EventHandler<HTMLButtonElement, MouseEvent> = (e) => {
+    if (typeof local.onClick === "function") local.onClick(e);
+    ctx.setOpen(false);
+  };
+
+  return (
+    <button type="button" onClick={handleClick} {...rest}>
+      {local.children}
+    </button>
+  );
+}
diff --git a/packages/core/src/components/alert-dialog/alert-dialog-content.tsx b/packages/core/src/components/alert-dialog/alert-dialog-content.tsx
new file mode 100644
index 0000000..a63aafa
--- /dev/null
+++ b/packages/core/src/components/alert-dialog/alert-dialog-content.tsx
@@ -0,0 +1,55 @@
+import type { JSX } from "solid-js";
+import { Show, createEffect, onCleanup, splitProps } from "solid-js";
+import { createFocusTrap } from "../../utilities/focus-trap/create-focus-trap";
+import { createScrollLock } from "../../utilities/scroll-lock/create-scroll-lock";
+import { useInternalAlertDialogContext } from "./alert-dialog-context";
+
+/** Props for AlertDialog.Content. */
+export interface AlertDialogContentProps extends JSX.HTMLAttributes<HTMLDivElement> {
+  forceMount?: boolean;
+  children?: JSX.Element;
+}
+
+/**
+ * AlertDialog content panel. Uses focus trap and scroll lock.
+ * Does NOT dismiss on Escape or outside pointer click (unlike Dialog).
+ */
+export function AlertDialogContent(props: AlertDialogContentProps): JSX.Element {
+  const [local, rest] = splitProps(props, ["children", "forceMount"]);
+  const ctx = useInternalAlertDialogContext();
+  let contentRef: HTMLDivElement | undefined;
+
+  const focusTrap = createFocusTrap(() => contentRef ?? null);
+  const scrollLock = createScrollLock();
+
+  createEffect(() => {
+    if (ctx.isOpen()) {
+      focusTrap.activate();
+      scrollLock.lock();
+    } else {
+      focusTrap.deactivate();
+      scrollLock.unlock();
+    }
+    onCleanup(() => {
+      focusTrap.deactivate();
+      scrollLock.unlock();
+    });
+  });
+
+  return (
+    <Show when={local.forceMount || ctx.isOpen()}>
+      <div
+        ref={contentRef}
+        id={ctx.contentId()}
+        role="alertdialog"
+        aria-modal="true"
+        aria-labelledby={ctx.titleId() ?? undefined}
+        aria-describedby={ctx.descriptionId() ?? undefined}
+        data-state={ctx.isOpen() ? "open" : "closed"}
+        {...rest}
+      >
+        {local.children}
+      </div>
+    </Show>
+  );
+}
diff --git a/packages/core/src/components/alert-dialog/alert-dialog-context.ts b/packages/core/src/components/alert-dialog/alert-dialog-context.ts
new file mode 100644
index 0000000..c57e0bf
--- /dev/null
+++ b/packages/core/src/components/alert-dialog/alert-dialog-context.ts
@@ -0,0 +1,52 @@
+import type { Accessor } from "solid-js";
+import { createContext, useContext } from "solid-js";
+
+/** Internal context shared between all AlertDialog parts. */
+export interface InternalAlertDialogContextValue {
+  isOpen: Accessor<boolean>;
+  setOpen: (open: boolean) => void;
+  contentId: Accessor<string>;
+  titleId: Accessor<string | undefined>;
+  setTitleId: (id: string | undefined) => void;
+  descriptionId: Accessor<string | undefined>;
+  setDescriptionId: (id: string | undefined) => void;
+}
+
+const InternalAlertDialogContext = createContext<InternalAlertDialogContextValue>();
+
+/**
+ * Returns the internal AlertDialog context. Throws if used outside <AlertDialog>.
+ */
+export function useInternalAlertDialogContext(): InternalAlertDialogContextValue {
+  const ctx = useContext(InternalAlertDialogContext);
+  if (!ctx) {
+    throw new Error(
+      "[PettyUI] AlertDialog parts must be used inside <AlertDialog>.\n" +
+        "  Fix: Wrap AlertDialog.Content, AlertDialog.Trigger, etc. inside <AlertDialog>.",
+    );
+  }
+  return ctx;
+}
+
+export const InternalAlertDialogContextProvider = InternalAlertDialogContext.Provider;
+
+/** Public context exposed to consumers via AlertDialog.useContext(). */
+export interface AlertDialogContextValue {
+  /** Whether the alert dialog is currently open. */
+  open: Accessor<boolean>;
+}
+
+const AlertDialogContext = createContext<AlertDialogContextValue>();
+
+/**
+ * Returns the public AlertDialog context. Throws if used outside <AlertDialog>.
+ */
+export function useAlertDialogContext(): AlertDialogContextValue {
+  const ctx = useContext(AlertDialogContext);
+  if (!ctx) {
+    throw new Error("[PettyUI] AlertDialog.useContext() called outside of <AlertDialog>.");
+  }
+  return ctx;
+}
+
+export const AlertDialogContextProvider = AlertDialogContext.Provider;
diff --git a/packages/core/src/components/alert-dialog/alert-dialog-description.tsx b/packages/core/src/components/alert-dialog/alert-dialog-description.tsx
new file mode 100644
index 0000000..2a9b571
--- /dev/null
+++ b/packages/core/src/components/alert-dialog/alert-dialog-description.tsx
@@ -0,0 +1,22 @@
+import type { JSX } from "solid-js";
+import { createUniqueId, onCleanup, onMount, splitProps } from "solid-js";
+import { useInternalAlertDialogContext } from "./alert-dialog-context";
+
+/** Props for AlertDialog.Description. */
+export interface AlertDialogDescriptionProps extends JSX.HTMLAttributes<HTMLParagraphElement> {
+  children?: JSX.Element;
+}
+
+/** Description for the AlertDialog. Registers its ID for aria-describedby. */
+export function AlertDialogDescription(props: AlertDialogDescriptionProps): JSX.Element {
+  const [local, rest] = splitProps(props, ["children"]);
+  const ctx = useInternalAlertDialogContext();
+  const id = createUniqueId();
+  onMount(() => ctx.setDescriptionId(id));
+  onCleanup(() => ctx.setDescriptionId(undefined));
+  return (
+    <p id={id} {...rest}>
+      {local.children}
+    </p>
+  );
+}
diff --git a/packages/core/src/components/alert-dialog/alert-dialog-overlay.tsx b/packages/core/src/components/alert-dialog/alert-dialog-overlay.tsx
new file mode 100644
index 0000000..a23c163
--- /dev/null
+++ b/packages/core/src/components/alert-dialog/alert-dialog-overlay.tsx
@@ -0,0 +1,19 @@
+import type { JSX } from "solid-js";
+import { Show, splitProps } from "solid-js";
+import { useInternalAlertDialogContext } from "./alert-dialog-context";
+
+/** Props for AlertDialog.Overlay. */
+export interface AlertDialogOverlayProps extends JSX.HTMLAttributes<HTMLDivElement> {
+  forceMount?: boolean;
+}
+
+/** Backdrop overlay behind AlertDialog content. */
+export function AlertDialogOverlay(props: AlertDialogOverlayProps): JSX.Element {
+  const [local, rest] = splitProps(props, ["forceMount"]);
+  const ctx = useInternalAlertDialogContext();
+  return (
+    <Show when={local.forceMount || ctx.isOpen()}>
+      <div aria-hidden="true" data-state={ctx.isOpen() ? "open" : "closed"} {...rest} />
+    </Show>
+  );
+}
diff --git a/packages/core/src/components/alert-dialog/alert-dialog-portal.tsx b/packages/core/src/components/alert-dialog/alert-dialog-portal.tsx
new file mode 100644
index 0000000..c5655ce
--- /dev/null
+++ b/packages/core/src/components/alert-dialog/alert-dialog-portal.tsx
@@ -0,0 +1,17 @@
+import type { JSX } from "solid-js";
+import { Portal } from "../../utilities/portal/portal";
+
+/** Props for AlertDialog.Portal. */
+export interface AlertDialogPortalProps {
+  target?: Element | null;
+  children: JSX.Element;
+}
+
+/** Renders children into a portal (defaults to document.body). */
+export function AlertDialogPortal(props: AlertDialogPortalProps): JSX.Element {
+  return props.target !== undefined ? (
+    <Portal target={props.target}>{props.children}</Portal>
+  ) : (
+    <Portal>{props.children}</Portal>
+  );
+}
diff --git a/packages/core/src/components/alert-dialog/alert-dialog-root.tsx b/packages/core/src/components/alert-dialog/alert-dialog-root.tsx
new file mode 100644
index 0000000..4d6c5fa
--- /dev/null
+++ b/packages/core/src/components/alert-dialog/alert-dialog-root.tsx
@@ -0,0 +1,59 @@
+import type { JSX } from "solid-js";
+import { createUniqueId } from "solid-js";
+import {
+  type CreateDisclosureStateOptions,
+  createDisclosureState,
+} from "../../primitives/create-disclosure-state";
+import { createRegisterId } from "../../primitives/create-register-id";
+import {
+  AlertDialogContextProvider,
+  InternalAlertDialogContextProvider,
+  type InternalAlertDialogContextValue,
+} from "./alert-dialog-context";
+
+/** Props for the AlertDialog root. */
+export interface AlertDialogRootProps {
+  open?: boolean;
+  defaultOpen?: boolean;
+  onOpenChange?: (open: boolean) => void;
+  children: JSX.Element;
+}
+
+/**
+ * Root component for AlertDialog. Manages open state and provides context.
+ */
+export function AlertDialogRoot(props: AlertDialogRootProps): JSX.Element {
+  const disclosure = createDisclosureState({
+    get open() {
+      return props.open;
+    },
+    get defaultOpen() {
+      return props.defaultOpen;
+    },
+    get onOpenChange() {
+      return props.onOpenChange;
+    },
+  } as CreateDisclosureStateOptions);
+
+  const contentId = createUniqueId();
+  const [titleId, setTitleId] = createRegisterId();
+  const [descriptionId, setDescriptionId] = createRegisterId();
+
+  const internalCtx: InternalAlertDialogContextValue = {
+    isOpen: disclosure.isOpen,
+    setOpen: (open) => (open ? disclosure.open() : disclosure.close()),
+    contentId: () => contentId,
+    titleId,
+    setTitleId,
+    descriptionId,
+    setDescriptionId,
+  };
+
+  return (
+    <InternalAlertDialogContextProvider value={internalCtx}>
+      <AlertDialogContextProvider value={{ open: disclosure.isOpen }}>
+        {props.children}
+      </AlertDialogContextProvider>
+    </InternalAlertDialogContextProvider>
+  );
+}
diff --git a/packages/core/src/components/alert-dialog/alert-dialog-title.tsx b/packages/core/src/components/alert-dialog/alert-dialog-title.tsx
new file mode 100644
index 0000000..4001bef
--- /dev/null
+++ b/packages/core/src/components/alert-dialog/alert-dialog-title.tsx
@@ -0,0 +1,22 @@
+import type { JSX } from "solid-js";
+import { createUniqueId, onCleanup, onMount, splitProps } from "solid-js";
+import { useInternalAlertDialogContext } from "./alert-dialog-context";
+
+/** Props for AlertDialog.Title. */
+export interface AlertDialogTitleProps extends JSX.HTMLAttributes<HTMLHeadingElement> {
+  children?: JSX.Element;
+}
+
+/** Title for the AlertDialog. Registers its ID for aria-labelledby. */
+export function AlertDialogTitle(props: AlertDialogTitleProps): JSX.Element {
+  const [local, rest] = splitProps(props, ["children"]);
+  const ctx = useInternalAlertDialogContext();
+  const id = createUniqueId();
+  onMount(() => ctx.setTitleId(id));
+  onCleanup(() => ctx.setTitleId(undefined));
+  return (
+    <h2 id={id} {...rest}>
+      {local.children}
+    </h2>
+  );
+}
diff --git a/packages/core/src/components/alert-dialog/alert-dialog-trigger.tsx b/packages/core/src/components/alert-dialog/alert-dialog-trigger.tsx
new file mode 100644
index 0000000..58add57
--- /dev/null
+++ b/packages/core/src/components/alert-dialog/alert-dialog-trigger.tsx
@@ -0,0 +1,25 @@
+import type { JSX } from "solid-js";
+import { splitProps } from "solid-js";
+import { useInternalAlertDialogContext } from "./alert-dialog-context";
+
+/** Props for AlertDialog.Trigger. */
+export interface AlertDialogTriggerProps extends JSX.ButtonHTMLAttributes<HTMLButtonElement> {
+  children?: JSX.Element;
+}
+
+/** Opens the AlertDialog when clicked. */
+export function AlertDialogTrigger(props: AlertDialogTriggerProps): JSX.Element {
+  const [local, rest] = splitProps(props, ["children", "onClick"]);
+  const ctx = useInternalAlertDialogContext();
+
+  const handleClick: JSX.EventHandler<HTMLButtonElement, MouseEvent> = (e) => {
+    if (typeof local.onClick === "function") local.onClick(e);
+    ctx.setOpen(true);
+  };
+
+  return (
+    <button type="button" aria-haspopup="dialog" onClick={handleClick} {...rest}>
+      {local.children}
+    </button>
+  );
+}
diff --git a/packages/core/src/components/alert-dialog/index.ts b/packages/core/src/components/alert-dialog/index.ts
new file mode 100644
index 0000000..f9507e7
--- /dev/null
+++ b/packages/core/src/components/alert-dialog/index.ts
@@ -0,0 +1,33 @@
+import { AlertDialogAction } from "./alert-dialog-action";
+import { AlertDialogCancel } from "./alert-dialog-cancel";
+import { AlertDialogContent } from "./alert-dialog-content";
+import { useAlertDialogContext } from "./alert-dialog-context";
+import { AlertDialogDescription } from "./alert-dialog-description";
+import { AlertDialogOverlay } from "./alert-dialog-overlay";
+import { AlertDialogPortal } from "./alert-dialog-portal";
+import { AlertDialogRoot } from "./alert-dialog-root";
+import { AlertDialogTitle } from "./alert-dialog-title";
+import { AlertDialogTrigger } from "./alert-dialog-trigger";
+
+export const AlertDialog = Object.assign(AlertDialogRoot, {
+  Content: AlertDialogContent,
+  Title: AlertDialogTitle,
+  Description: AlertDialogDescription,
+  Trigger: AlertDialogTrigger,
+  Cancel: AlertDialogCancel,
+  Action: AlertDialogAction,
+  Portal: AlertDialogPortal,
+  Overlay: AlertDialogOverlay,
+  useContext: useAlertDialogContext,
+});
+
+export type { AlertDialogRootProps } from "./alert-dialog-root";
+export type { AlertDialogContentProps } from "./alert-dialog-content";
+export type { AlertDialogTitleProps } from "./alert-dialog-title";
+export type { AlertDialogDescriptionProps } from "./alert-dialog-description";
+export type { AlertDialogTriggerProps } from "./alert-dialog-trigger";
+export type { AlertDialogCancelProps } from "./alert-dialog-cancel";
+export type { AlertDialogActionProps } from "./alert-dialog-action";
+export type { AlertDialogPortalProps } from "./alert-dialog-portal";
+export type { AlertDialogOverlayProps } from "./alert-dialog-overlay";
+export type { AlertDialogContextValue } from "./alert-dialog-context";
diff --git a/packages/core/tests/components/alert-dialog/alert-dialog.test.tsx b/packages/core/tests/components/alert-dialog/alert-dialog.test.tsx
new file mode 100644
index 0000000..0411e82
--- /dev/null
+++ b/packages/core/tests/components/alert-dialog/alert-dialog.test.tsx
@@ -0,0 +1,108 @@
+// packages/core/tests/components/alert-dialog/alert-dialog.test.tsx
+import { fireEvent, render, screen } from "@solidjs/testing-library";
+import { describe, expect, it } from "vitest";
+import { AlertDialog } from "../../../src/components/alert-dialog/index";
+
+describe("AlertDialog", () => {
+  it("content has role=alertdialog", () => {
+    render(() => (
+      <AlertDialog defaultOpen>
+        <AlertDialog.Content>
+          <AlertDialog.Title>Confirm</AlertDialog.Title>
+          <AlertDialog.Description>Are you sure?</AlertDialog.Description>
+        </AlertDialog.Content>
+      </AlertDialog>
+    ));
+    expect(screen.getByRole("alertdialog")).toBeTruthy();
+  });
+
+  it("content has aria-modal=true", () => {
+    render(() => (
+      <AlertDialog defaultOpen>
+        <AlertDialog.Content>
+          <AlertDialog.Title>Confirm</AlertDialog.Title>
+        </AlertDialog.Content>
+      </AlertDialog>
+    ));
+    expect(screen.getByRole("alertdialog").getAttribute("aria-modal")).toBe("true");
+  });
+
+  it("content is linked to title via aria-labelledby", () => {
+    render(() => (
+      <AlertDialog defaultOpen>
+        <AlertDialog.Content>
+          <AlertDialog.Title>Delete file?</AlertDialog.Title>
+        </AlertDialog.Content>
+      </AlertDialog>
+    ));
+    const dialog = screen.getByRole("alertdialog");
+    const title = screen.getByText("Delete file?");
+    expect(dialog.getAttribute("aria-labelledby")).toBe(title.id);
+  });
+
+  it("content is linked to description via aria-describedby", () => {
+    render(() => (
+      <AlertDialog defaultOpen>
+        <AlertDialog.Content>
+          <AlertDialog.Title>Confirm</AlertDialog.Title>
+          <AlertDialog.Description>This cannot be undone.</AlertDialog.Description>
+        </AlertDialog.Content>
+      </AlertDialog>
+    ));
+    const dialog = screen.getByRole("alertdialog");
+    const desc = screen.getByText("This cannot be undone.");
+    expect(dialog.getAttribute("aria-describedby")).toBe(desc.id);
+  });
+
+  it("trigger opens the dialog", () => {
+    render(() => (
+      <AlertDialog>
+        <AlertDialog.Trigger>Delete</AlertDialog.Trigger>
+        <AlertDialog.Content>
+          <AlertDialog.Title>Confirm</AlertDialog.Title>
+        </AlertDialog.Content>
+      </AlertDialog>
+    ));
+    expect(screen.queryByRole("alertdialog")).toBeNull();
+    fireEvent.click(screen.getByText("Delete"));
+    expect(screen.getByRole("alertdialog")).toBeTruthy();
+  });
+
+  it("Cancel button closes the dialog", () => {
+    render(() => (
+      <AlertDialog defaultOpen>
+        <AlertDialog.Content>
+          <AlertDialog.Title>Confirm</AlertDialog.Title>
+          <AlertDialog.Cancel>Cancel</AlertDialog.Cancel>
+        </AlertDialog.Content>
+      </AlertDialog>
+    ));
+    fireEvent.click(screen.getByText("Cancel"));
+    expect(screen.queryByRole("alertdialog")).toBeNull();
+  });
+
+  it("Action button closes the dialog", () => {
+    render(() => (
+      <AlertDialog defaultOpen>
+        <AlertDialog.Content>
+          <AlertDialog.Title>Are you sure?</AlertDialog.Title>
+          <AlertDialog.Action>Confirm</AlertDialog.Action>
+        </AlertDialog.Content>
+      </AlertDialog>
+    ));
+    fireEvent.click(screen.getByText("Confirm"));
+    expect(screen.queryByRole("alertdialog")).toBeNull();
+  });
+
+  it("Escape key does NOT close alert dialog", () => {
+    render(() => (
+      <AlertDialog defaultOpen>
+        <AlertDialog.Content>
+          <AlertDialog.Title>Confirm</AlertDialog.Title>
+        </AlertDialog.Content>
+      </AlertDialog>
+    ));
+    fireEvent.keyDown(document, { key: "Escape" });
+    expect(screen.getByRole("alertdialog")).toBeTruthy();
+  });
+});