diff --git a/site/e2e/tests/deployment/idpOrgSync.spec.ts b/site/e2e/tests/deployment/idpOrgSync.spec.ts
index 59fccb440400b..6d50969298301 100644
--- a/site/e2e/tests/deployment/idpOrgSync.spec.ts
+++ b/site/e2e/tests/deployment/idpOrgSync.spec.ts
@@ -78,7 +78,7 @@ test.describe("IdpOrgSyncPage", () => {
 		).toBeVisible();
 	});
 
-	test("toggle default organization assignment", async ({ page }) => {
+	test("toggle off default organization assignment", async ({ page }) => {
 		requiresLicense();
 		await page.goto("/deployment/idp-org-sync", {
 			waitUntil: "domcontentloaded",
@@ -89,6 +89,12 @@ test.describe("IdpOrgSyncPage", () => {
 		});
 		await toggle.click();
 
+		const dialog = page.getByRole("dialog");
+		await expect(dialog).toBeVisible();
+
+		await dialog.getByRole("button", { name: "Confirm" }).click();
+		await expect(dialog).not.toBeVisible();
+
 		await expect(
 			page.getByText("Organization sync settings updated."),
 		).toBeVisible();
diff --git a/site/src/components/Button/Button.tsx b/site/src/components/Button/Button.tsx
index 8b83149e3bb1e..b0a460eca8a3c 100644
--- a/site/src/components/Button/Button.tsx
+++ b/site/src/components/Button/Button.tsx
@@ -8,7 +8,12 @@ import { type FC, forwardRef } from "react";
 import { cn } from "utils/cn";
 
 export const buttonVariants = cva(
-	"inline-flex items-center justify-center gap-2 whitespace-nowrap rounded-md text-sm font-medium transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-content-link disabled:pointer-events-none disabled:text-content-disabled [&_svg]:pointer-events-none [&_svg]:size-4 [&_svg]:shrink-0 font-semibold border-solid cursor-pointer",
+	`inline-flex items-center justify-center gap-2 whitespace-nowrap
+	border-solid rounded-md transition-colors
+	text-sm font-semibold font-medium  cursor-pointer
+	focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-content-link
+	disabled:pointer-events-none disabled:text-content-disabled
+	[&_svg]:pointer-events-none [&_svg]:size-4 [&_svg]:shrink-0`,
 	{
 		variants: {
 			variant: {
diff --git a/site/src/components/Dialog/Dialog.tsx b/site/src/components/Dialog/Dialog.tsx
index dbcc0efc944cd..0770ec62ae735 100644
--- a/site/src/components/Dialog/Dialog.tsx
+++ b/site/src/components/Dialog/Dialog.tsx
@@ -3,7 +3,6 @@
  * @see {@link https://ui.shadcn.com/docs/components/dialog}
  */
 import * as DialogPrimitive from "@radix-ui/react-dialog";
-import { X } from "lucide-react";
 import {
 	type ComponentPropsWithoutRef,
 	type ElementRef,
@@ -46,29 +45,19 @@ export const DialogContent = forwardRef<
 		<DialogPrimitive.Content
 			ref={ref}
 			className={cn(
-				`fixed left-[50%] top-[50%] z-50 grid w-full max-w-lg
-				gap-4 border bg-background p-6 shadow-lg duration-200 sm:rounded-lg
-				translate-x-[-50%] translate-y-[-50%]
-				data-[state=open]:animate-in data-[state=closed]:animate-out
-				data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0
-				data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95
-				data-[state=closed]:slide-out-to-left-1/2 data-[state=closed]:slide-out-to-top-[48%]
-				data-[state=open]:slide-in-from-left-1/2 data-[state=open]:slide-in-from-top-[48%]`,
+				`fixed left-[50%] top-[50%] z-50 grid w-full max-w-lg gap-4
+				 border border-solid border-border bg-surface-primary p-8 shadow-lg duration-200 sm:rounded-lg
+				 translate-x-[-50%] translate-y-[-50%]
+				 data-[state=open]:animate-in data-[state=closed]:animate-out
+				 data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0
+				 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95
+				 data-[state=closed]:slide-out-to-left-1/2 data-[state=closed]:slide-out-to-top-[48%]
+				 data-[state=open]:slide-in-from-left-1/2 data-[state=open]:slide-in-from-top-[48%]`,
 				className,
 			)}
 			{...props}
 		>
 			{children}
-			<DialogPrimitive.Close
-				className={`absolute right-4 top-4 rounded-sm opacity-70 ring-offset-background transition-opacity
-			hover:opacity-100
-			focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2
-			disabled:pointer-events-none
-			data-[state=open]:bg-surface-secondary data-[state=open]:text-content-disabled`}
-			>
-				<X className="h-4 w-4" />
-				<span className="sr-only">Close</span>
-			</DialogPrimitive.Close>
 		</DialogPrimitive.Content>
 	</DialogPortal>
 ));
@@ -106,7 +95,7 @@ export const DialogTitle = forwardRef<
 	<DialogPrimitive.Title
 		ref={ref}
 		className={cn(
-			"text-lg font-semibold leading-none tracking-tight",
+			"text-xl m-0 text-content-primary font-semibold leading-none tracking-tight",
 			className,
 		)}
 		{...props}
@@ -119,7 +108,7 @@ export const DialogDescription = forwardRef<
 >(({ className, ...props }, ref) => (
 	<DialogPrimitive.Description
 		ref={ref}
-		className={cn("text-sm text-content-disabled", className)}
+		className={cn("text-sm text-content-secondary", className)}
 		{...props}
 	/>
 ));
diff --git a/site/src/pages/DeploymentSettingsPage/IdpOrgSyncPage/IdpOrgSyncPageView.stories.tsx b/site/src/pages/DeploymentSettingsPage/IdpOrgSyncPage/IdpOrgSyncPageView.stories.tsx
index 99742b82e6d17..8d02e1f248833 100644
--- a/site/src/pages/DeploymentSettingsPage/IdpOrgSyncPage/IdpOrgSyncPageView.stories.tsx
+++ b/site/src/pages/DeploymentSettingsPage/IdpOrgSyncPage/IdpOrgSyncPageView.stories.tsx
@@ -1,4 +1,5 @@
 import type { Meta, StoryObj } from "@storybook/react";
+import { userEvent, within } from "@storybook/test";
 import {
 	MockOrganization,
 	MockOrganization2,
@@ -48,3 +49,18 @@ export const MissingGroups: Story = {
 		organizationSyncSettings: MockOrganizationSyncSettings,
 	},
 };
+
+export const AssignDefaultOrgWarningDialog: Story = {
+	args: {
+		organizationSyncSettings: MockOrganizationSyncSettings,
+		organizations: [MockOrganization, MockOrganization2],
+	},
+	play: async ({ canvasElement }) => {
+		const canvas = within(canvasElement);
+		await userEvent.click(
+			canvas.getByRole("switch", {
+				name: "Assign Default Organization",
+			}),
+		);
+	},
+};
diff --git a/site/src/pages/DeploymentSettingsPage/IdpOrgSyncPage/IdpOrgSyncPageView.tsx b/site/src/pages/DeploymentSettingsPage/IdpOrgSyncPage/IdpOrgSyncPageView.tsx
index 470bf897fd90e..ae90e26c3aa7c 100644
--- a/site/src/pages/DeploymentSettingsPage/IdpOrgSyncPage/IdpOrgSyncPageView.tsx
+++ b/site/src/pages/DeploymentSettingsPage/IdpOrgSyncPage/IdpOrgSyncPageView.tsx
@@ -1,4 +1,3 @@
-import Skeleton from "@mui/material/Skeleton";
 import Table from "@mui/material/Table";
 import TableBody from "@mui/material/TableBody";
 import TableCell from "@mui/material/TableCell";
@@ -12,6 +11,14 @@ import type {
 import { ErrorAlert } from "components/Alert/ErrorAlert";
 import { Button } from "components/Button/Button";
 import { ChooseOne, Cond } from "components/Conditionals/ChooseOne";
+import {
+	Dialog,
+	DialogContent,
+	DialogDescription,
+	DialogFooter,
+	DialogHeader,
+	DialogTitle,
+} from "components/Dialog/Dialog";
 import { EmptyState } from "components/EmptyState/EmptyState";
 import {
 	HelpTooltip,
@@ -26,10 +33,6 @@ import {
 	type Option,
 } from "components/MultiSelectCombobox/MultiSelectCombobox";
 import { Switch } from "components/Switch/Switch";
-import {
-	TableLoaderSkeleton,
-	TableRowSkeleton,
-} from "components/TableLoader/TableLoader";
 import { useFormik } from "formik";
 import { Plus, SquareArrowOutUpRight, Trash } from "lucide-react";
 import { type FC, useState } from "react";
@@ -74,6 +77,7 @@ export const IdpOrgSyncPageView: FC<IdpSyncPageViewProps> = ({
 	const organizationMappingCount = form.values.mapping
 		? Object.entries(form.values.mapping).length
 		: 0;
+	const [isDialogOpen, setIsDialogOpen] = useState(false);
 
 	const getOrgNames = (orgIds: readonly string[]) => {
 		return orgIds.map(
@@ -136,11 +140,15 @@ export const IdpOrgSyncPageView: FC<IdpSyncPageViewProps> = ({
 										id={ORGANIZATION_ASSIGN_DEFAULT_ID}
 										checked={form.values.organization_assign_default}
 										onCheckedChange={async (checked) => {
-											void form.setFieldValue(
-												"organization_assign_default",
-												checked,
-											);
-											form.handleSubmit();
+											if (!checked) {
+												setIsDialogOpen(true);
+											} else {
+												void form.setFieldValue(
+													"organization_assign_default",
+													checked,
+												);
+												form.handleSubmit();
+											}
 										}}
 									/>
 									<span className="flex flex-row items-center gap-1">
@@ -234,6 +242,36 @@ export const IdpOrgSyncPageView: FC<IdpSyncPageViewProps> = ({
 					</div>
 				</fieldset>
 			</form>
+
+			<Dialog open={isDialogOpen} onOpenChange={setIsDialogOpen}>
+				<DialogContent className="flex flex-col gap-12 max-w-lg">
+					<DialogHeader className="flex flex-col gap-4">
+						<DialogTitle>
+							Switch off default organization assignment
+						</DialogTitle>
+						<DialogDescription>
+							Warning: This will remove all users from the default organization
+							unless otherwise specified in an organization mapping defined
+							below.
+						</DialogDescription>
+					</DialogHeader>
+					<DialogFooter className="flex flex-row">
+						<Button variant="outline" onClick={() => setIsDialogOpen(false)}>
+							Cancel
+						</Button>
+						<Button
+							onClick={() => {
+								void form.setFieldValue("organization_assign_default", false);
+								setIsDialogOpen(false);
+								form.handleSubmit();
+							}}
+							type="submit"
+						>
+							Confirm
+						</Button>
+					</DialogFooter>
+				</DialogContent>
+			</Dialog>
 		</div>
 	);
 };
@@ -318,31 +356,14 @@ const OrganizationRow: FC<OrganizationRowProps> = ({
 	);
 };
 
-const TableLoader = () => {
-	return (
-		<TableLoaderSkeleton>
-			<TableRowSkeleton>
-				<TableCell>
-					<Skeleton variant="text" width="25%" />
-				</TableCell>
-				<TableCell>
-					<Skeleton variant="text" width="25%" />
-				</TableCell>
-				<TableCell>
-					<Skeleton variant="text" width="10%" />
-				</TableCell>
-			</TableRowSkeleton>
-		</TableLoaderSkeleton>
-	);
-};
-
 export const AssignDefaultOrgHelpTooltip: FC = () => {
 	return (
 		<HelpTooltip>
 			<HelpTooltipTrigger />
 			<HelpTooltipContent>
 				<HelpTooltipText>
-					Disabling will remove all users from the default organization.
+					Disabling will remove all users from the default organization if a
+					mapping for the default organization is not defined.
 				</HelpTooltipText>
 			</HelpTooltipContent>
 		</HelpTooltip>