diff --git a/tests/MultiSelect/MultiSelect.test.ts b/tests/MultiSelect/MultiSelect.test.ts
index aed26b4a..7d2b8fae 100644
--- a/tests/MultiSelect/MultiSelect.test.ts
+++ b/tests/MultiSelect/MultiSelect.test.ts
@@ -2,7 +2,13 @@ import { render, screen } from "@testing-library/svelte";
 import { MultiSelect } from "carbon-components-svelte";
 import { user } from "../setup-tests";
 
-describe("MultiSelect sorts items correctly", () => {
+const items = [
+  { id: "0", text: "Slack" },
+  { id: "1", text: "Email" },
+  { id: "2", text: "Fax" },
+] as const;
+
+describe("MultiSelect", () => {
   /** Opens the dropdown. */
   const openMenu = async () =>
     await user.click(
@@ -29,96 +35,317 @@ describe("MultiSelect sorts items correctly", () => {
   const nthRenderedOptionText = (index: number) =>
     screen.queryAllByRole("option").at(index)?.textContent?.trim();
 
-  it("initially sorts items alphabetically", async () => {
-    render(MultiSelect, {
-      items: [
-        { id: "1", text: "C" },
-        { id: "3", text: "A" },
-        { id: "2", text: "B" },
-      ],
+  describe("sorting behavior", () => {
+    it("initially sorts items alphabetically", async () => {
+      render(MultiSelect, {
+        items: [
+          { id: "1", text: "C" },
+          { id: "3", text: "A" },
+          { id: "2", text: "B" },
+        ],
+      });
+
+      // Initially, items should be sorted alphabetically.
+      await openMenu();
+      expect(nthRenderedOptionText(0)).toBe("A");
+      expect(nthRenderedOptionText(1)).toBe("B");
+      expect(nthRenderedOptionText(2)).toBe("C");
     });
 
-    await openMenu();
-    expect(nthRenderedOptionText(0)).toBe("A");
-    expect(nthRenderedOptionText(1)).toBe("B");
-    expect(nthRenderedOptionText(2)).toBe("C");
+    it("immediately moves selected items to the top (with selectionFeedback: top)", async () => {
+      render(MultiSelect, {
+        items: [
+          { id: "3", text: "C" },
+          { id: "1", text: "A" },
+          { id: "2", text: "B" },
+        ],
+        selectionFeedback: "top",
+      });
+
+      // Initially, items should be sorted alphabetically.
+      await openMenu();
+      expect(nthRenderedOptionText(0)).toBe("A");
+
+      await toggleOption("C");
+      expect(nthRenderedOptionText(0)).toBe("C");
+
+      await toggleOption("C");
+      expect(nthRenderedOptionText(0)).toBe("A");
+    });
+
+    it("sorts newly-toggled items only after the dropdown is reoponed (with selectionFeedback: top-after-reopen)", async () => {
+      render(MultiSelect, {
+        items: [
+          { id: "3", text: "C" },
+          { id: "1", text: "A" },
+          { id: "2", text: "B" },
+        ],
+      });
+
+      // Initially, items should be sorted alphabetically.
+      await openMenu();
+      expect(nthRenderedOptionText(0)).toBe("A");
+
+      // While the menu is still open, a newly-selected item should not move.
+      await toggleOption("C");
+      expect(nthRenderedOptionText(0)).toBe("A");
+
+      // The newly-selected item should move after the menu is closed and
+      // re-opened.
+      await closeMenu();
+      await openMenu();
+      expect(nthRenderedOptionText(0)).toBe("C");
+
+      // A deselected item should not move while the dropdown is still open.
+      await toggleOption("C");
+      expect(nthRenderedOptionText(0)).toBe("C");
+
+      // The deselected item should move after closing and re-opening the dropdown.
+      await closeMenu();
+      await openMenu();
+      expect(nthRenderedOptionText(0)).toBe("A");
+    });
+
+    it("never moves selected items to the top (with selectionFeedback: fixed)", async () => {
+      render(MultiSelect, {
+        items: [
+          { id: "3", text: "C" },
+          { id: "1", text: "A" },
+          { id: "2", text: "B" },
+        ],
+        selectionFeedback: "fixed",
+      });
+
+      // Items should be sorted alphabetically.
+      await openMenu();
+      expect(nthRenderedOptionText(0)).toBe("A");
+
+      // A newly-selected item should not move after the selection is made.
+      await toggleOption("C");
+      expect(nthRenderedOptionText(0)).toBe("A");
+
+      // The newly-selected item also shouldn’t move after the dropdown is closed
+      // and reopened.
+      await closeMenu();
+      await openMenu();
+      expect(nthRenderedOptionText(0)).toBe("A");
+    });
   });
 
-  it("immediately moves selected items to the top (with selectionFeedback: top)", async () => {
-    render(MultiSelect, {
-      items: [
-        { id: "3", text: "C" },
-        { id: "1", text: "A" },
-        { id: "2", text: "B" },
-      ],
-      selectionFeedback: "top",
+  describe("filtering behavior", () => {
+    it("should filter items based on input value", async () => {
+      render(MultiSelect, {
+        items,
+        filterable: true,
+        placeholder: "Filter items...",
+      });
+
+      await openMenu();
+      const input = screen.getByPlaceholderText("Filter items...");
+      await user.type(input, "em");
+
+      expect(screen.queryByText("Slack")).not.toBeInTheDocument();
+      expect(screen.getByText("Email")).toBeInTheDocument();
+      expect(screen.queryByText("Fax")).not.toBeInTheDocument();
     });
 
-    await openMenu();
-    expect(nthRenderedOptionText(0)).toBe("A");
+    it("should use custom filter function", async () => {
+      render(MultiSelect, {
+        items,
+        filterable: true,
+        filterItem: (item, value) =>
+          item.text.toLowerCase().startsWith(value.toLowerCase()),
+      });
 
-    await toggleOption("C");
-    expect(nthRenderedOptionText(0)).toBe("C");
+      await openMenu();
+      const input = screen.getByRole("combobox");
+      await user.type(input, "e");
 
-    await toggleOption("C");
-    expect(nthRenderedOptionText(0)).toBe("A");
+      expect(screen.queryByText("Slack")).not.toBeInTheDocument();
+      expect(screen.getByText("Email")).toBeInTheDocument();
+      expect(screen.queryByText("Fax")).not.toBeInTheDocument();
+    });
+
+    // TODO(bug): ListBoxSelection aria-labels should be user-friendly
+    it.skip("should clear filter on selection clear", async () => {
+      render(MultiSelect, {
+        items,
+        filterable: true,
+        selectedIds: ["0"],
+      });
+
+      const clearButton = screen.getByLabelText("Clear all");
+      await user.click(clearButton);
+
+      const input = screen.getByRole("combobox");
+      expect(input).toHaveValue("");
+    });
   });
 
-  it("sorts newly-toggled items only after the dropdown is reoponed (with selectionFeedback: top-after-reopen)", async () => {
-    render(MultiSelect, {
-      items: [
-        { id: "3", text: "C" },
-        { id: "1", text: "A" },
-        { id: "2", text: "B" },
-      ],
+  describe("keyboard navigation", () => {
+    it("should handle arrow keys for navigation", async () => {
+      render(MultiSelect, { items });
+
+      await openMenu();
+      await user.keyboard("{ArrowDown}");
+
+      const options = screen.getAllByRole("option");
+      expect(options[0]).toHaveClass("bx--list-box__menu-item--highlighted");
     });
 
-    // Initially, items should be sorted alphabetically.
-    await openMenu();
-    expect(nthRenderedOptionText(0)).toBe("A");
+    it("should select item with Enter key", async () => {
+      const { component } = render(MultiSelect, { items });
+      const selectHandler = vi.fn();
+      component.$on("select", selectHandler);
 
-    // While the menu is still open, a newly-selected item should not move.
-    await toggleOption("C");
-    expect(nthRenderedOptionText(0)).toBe("A");
+      await openMenu();
+      await user.keyboard("{ArrowDown}");
+      await user.keyboard("{Enter}");
 
-    // The newly-selected item should move after the menu is closed and
-    // re-opened.
-    await closeMenu();
-    await openMenu();
-    expect(nthRenderedOptionText(0)).toBe("C");
+      expect(selectHandler).toHaveBeenCalled();
+    });
 
-    // A deselected item should not move while the dropdown is still open.
-    await toggleOption("C");
-    expect(nthRenderedOptionText(0)).toBe("C");
+    it("should close menu with Escape key", async () => {
+      render(MultiSelect, { items });
 
-    // The deselected item should move after closing and re-opening the dropdown.
-    await closeMenu();
-    await openMenu();
-    expect(nthRenderedOptionText(0)).toBe("A");
+      await openMenu();
+      await user.keyboard("{Escape}");
+
+      const button = screen.getByRole("button");
+      expect(button).toHaveAttribute("aria-expanded", "false");
+    });
   });
 
-  it("never moves selected items to the top (with selectionFeedback: fixed)", async () => {
-    render(MultiSelect, {
-      items: [
-        { id: "3", text: "C" },
-        { id: "1", text: "A" },
-        { id: "2", text: "B" },
-      ],
-      selectionFeedback: "fixed",
+  describe("accessibility", () => {
+    it("should handle hidden label", () => {
+      render(MultiSelect, {
+        items,
+        titleText: "Contact methods",
+        hideLabel: true,
+      });
+
+      const label = screen.getByText("Contact methods");
+      expect(label).toHaveClass("bx--visually-hidden");
     });
 
-    // Items should be sorted alphabetically.
-    await openMenu();
-    expect(nthRenderedOptionText(0)).toBe("A");
+    it("should handle custom aria-label", async () => {
+      render(MultiSelect, {
+        items,
+        "aria-label": "Custom label",
+      });
 
-    // A newly-selected item should not move after the selection is made.
-    await toggleOption("C");
-    expect(nthRenderedOptionText(0)).toBe("A");
+      await openMenu();
+      const menu = screen.getByLabelText("Custom label");
+      expect(menu).toBeInTheDocument();
+    });
+  });
 
-    // The newly-selected item also shouldn’t move after the dropdown is closed
-    // and reopened.
-    await closeMenu();
-    await openMenu();
-    expect(nthRenderedOptionText(0)).toBe("A");
+  describe("variants and states", () => {
+    it("should render in light variant", async () => {
+      render(MultiSelect, {
+        items,
+        light: true,
+      });
+
+      await openMenu();
+      const listBox = screen.getByRole("listbox").closest(".bx--list-box");
+      expect(listBox).toHaveClass("bx--list-box--light");
+    });
+
+    it("should render in inline variant", () => {
+      render(MultiSelect, {
+        items,
+        type: "inline",
+      });
+
+      const wrapper = screen
+        .getByRole("button")
+        .closest(".bx--multi-select__wrapper");
+      expect(wrapper).toHaveClass("bx--multi-select__wrapper--inline");
+    });
+
+    it("should handle invalid state", () => {
+      render(MultiSelect, {
+        items,
+        invalid: true,
+        invalidText: "Invalid selection",
+      });
+
+      expect(screen.getByText("Invalid selection")).toBeInTheDocument();
+      const wrapper = screen.getByRole("button").closest(".bx--list-box");
+      expect(wrapper).toHaveClass("bx--multi-select--invalid");
+    });
+
+    it("should handle warning state", () => {
+      render(MultiSelect, {
+        items,
+        warn: true,
+        warnText: "Warning message",
+      });
+
+      expect(screen.getByText("Warning message")).toBeInTheDocument();
+      const wrapper = screen.getByRole("button").closest(".bx--list-box");
+      expect(wrapper).toHaveClass("bx--list-box--warning");
+    });
+
+    it("should handle disabled state", () => {
+      render(MultiSelect, { items, disabled: true });
+
+      const field = screen.getByRole("button");
+      expect(field).toHaveAttribute("aria-disabled", "true");
+      expect(field).toHaveAttribute("tabindex", "-1");
+      expect(field.closest(".bx--multi-select")).toHaveAttribute(
+        "tabindex",
+        "-1",
+      );
+    });
+
+    it("should handle disabled items", async () => {
+      const itemsWithDisabled = [
+        { id: "0", text: "Slack" },
+        { id: "1", text: "Email", disabled: true },
+        { id: "2", text: "Fax" },
+      ];
+
+      render(MultiSelect, {
+        items: itemsWithDisabled,
+      });
+
+      await openMenu();
+      const emailOption = screen
+        .getByText("Email")
+        .closest(".bx--list-box__menu-item");
+      expect(emailOption).toHaveAttribute("disabled");
+    });
+  });
+
+  describe("custom formatting", () => {
+    it("should handle custom itemToString", () => {
+      render(MultiSelect, {
+        items,
+        selectedIds: ["0"],
+        itemToString: (item) => `${item.text} (${item.id})`,
+      });
+
+      expect(screen.getByText("Slack (0)")).toBeInTheDocument();
+    });
+
+    it("should handle custom itemToInput", async () => {
+      render(MultiSelect, {
+        items,
+        itemToInput: (item) => ({
+          name: `contact_${item.id}`,
+          value: item.text.toLowerCase(),
+        }),
+      });
+
+      await openMenu();
+      const checkbox = screen.getByText("Slack");
+      const checkboxWrapper = checkbox.closest(".bx--checkbox-wrapper");
+      assert(checkboxWrapper);
+
+      const checkboxInput = checkboxWrapper.querySelector("input");
+      expect(checkboxInput).toHaveAttribute("name", "contact_0");
+    });
   });
 });