diff --git a/locales/en-US.yml b/locales/en-US.yml
index 5f3c74754e..a786e178cb 100644
--- a/locales/en-US.yml
+++ b/locales/en-US.yml
@@ -1080,6 +1080,7 @@ noteId: "Post ID"
 signupsDisabled: "Signups on this server are currently disabled, but you can always sign up at another server! If you have an invitation code for this server, please enter it below."
 findOtherInstance: "Find another server"
 apps: "Apps"
+sendModMail: "Send Moderation Notice"
 
 _sensitiveMediaDetection:
   description: "Reduces the effort of server moderation through automatically recognizing\
diff --git a/packages/backend/src/server/api/endpoints.ts b/packages/backend/src/server/api/endpoints.ts
index e6f8f7ee6a..6a98fdfb28 100644
--- a/packages/backend/src/server/api/endpoints.ts
+++ b/packages/backend/src/server/api/endpoints.ts
@@ -53,6 +53,7 @@ import * as ep___admin_resetPassword from "./endpoints/admin/reset-password.js";
 import * as ep___admin_resolveAbuseUserReport from "./endpoints/admin/resolve-abuse-user-report.js";
 import * as ep___admin_search_indexAll from "./endpoints/admin/search/index-all.js";
 import * as ep___admin_sendEmail from "./endpoints/admin/send-email.js";
+import * as ep___admin_sendModMail from "./endpoints/admin/send-mod-mail.js";
 import * as ep___admin_serverInfo from "./endpoints/admin/server-info.js";
 import * as ep___admin_showModerationLogs from "./endpoints/admin/show-moderation-logs.js";
 import * as ep___admin_showUser from "./endpoints/admin/show-user.js";
@@ -403,6 +404,7 @@ const eps = [
 	["admin/resolve-abuse-user-report", ep___admin_resolveAbuseUserReport],
 	["admin/search/index-all", ep___admin_search_indexAll],
 	["admin/send-email", ep___admin_sendEmail],
+	["admin/send-mod-mail", ep___admin_sendModMail],
 	["admin/server-info", ep___admin_serverInfo],
 	["admin/show-moderation-logs", ep___admin_showModerationLogs],
 	["admin/show-user", ep___admin_showUser],
diff --git a/packages/backend/src/server/api/endpoints/admin/send-mod-mail.ts b/packages/backend/src/server/api/endpoints/admin/send-mod-mail.ts
new file mode 100644
index 0000000000..b6f3111ce2
--- /dev/null
+++ b/packages/backend/src/server/api/endpoints/admin/send-mod-mail.ts
@@ -0,0 +1,68 @@
+import * as sanitizeHtml from "sanitize-html";
+import define from "../../define.js";
+import { Users, UserProfiles } from "@/models/index.js";
+import { ApiError } from "../../error.js";
+import { sendEmail } from "@/services/send-email.js";
+import { createNotification } from "@/services/create-notification.js";
+
+export const meta = {
+	tags: ["users"],
+
+	requireCredential: true,
+	requireModerator: true,
+
+	description: "Send a mod mail.",
+
+	errors: {
+		noSuchUser: {
+			message: "No such user.",
+			code: "NO_SUCH_USER",
+			id: "1acefcb5-0959-43fd-9685-b48305736cb5",
+		},
+		noEmail: {
+			message: "No email for user.",
+			code: "NO_EMAIL",
+			id: "ac9d2d22-ef73-11ed-a05b-0242ac120003",
+		},
+	},
+} as const;
+
+export const paramDef = {
+	type: "object",
+	properties: {
+		userId: { type: "string", format: "misskey:id" },
+		comment: { type: "string", minLength: 1, maxLength: 2048 },
+	},
+	required: ["userId", "comment"],
+} as const;
+
+export default define(meta, paramDef, async (ps) => {
+	const [user, profile] = await Promise.all([
+		Users.findOneBy({ id: ps.userId }),
+		UserProfiles.findOneBy({ userId: ps.userId }),
+	]);
+
+	if (user == null || profile == null) {
+		throw new ApiError(meta.errors.noSuchUser);
+	}
+
+	createNotification(user.id, "app", {
+		customBody: ps.comment,
+		customHeader: "Moderation Notice",
+		customIcon: "/static-assets/badges/info.png",
+	});
+
+	setImmediate(async () => {
+		const email = profile.email;
+		if (email == null) {
+			throw new ApiError(meta.errors.noEmail);
+		}
+
+		sendEmail(
+			email,
+			"Moderation notice",
+			sanitizeHtml(ps.comment),
+			sanitizeHtml(ps.comment),
+		);
+	});
+});
diff --git a/packages/client/src/pages/user-info.vue b/packages/client/src/pages/user-info.vue
index 12321c2ba2..f66069a35d 100644
--- a/packages/client/src/pages/user-info.vue
+++ b/packages/client/src/pages/user-info.vue
@@ -218,6 +218,12 @@
 							>{{ i18n.ts.deleteAccount }}</FormButton
 						>
 					</div>
+					<MkButton
+						v-if="user.host == null && iAmModerator"
+						inline
+						@click="sendModMail"
+						>{{ i18n.ts.sendModMail }}</MkButton
+					>
 					<FormTextarea
 						v-model="moderationNote"
 						manual-save
@@ -486,6 +492,17 @@ async function toggleModerator(v) {
 	await refreshUser();
 }
 
+async function sendModMail() {
+	const { canceled, result } = await os.inputParagraph({
+		title: "Mod mail",
+	});
+	if (canceled) return;
+	await os.apiWithDialog("admin/send-mod-mail", {
+		userId: user.id,
+		text: result,
+	});
+};
+
 async function deleteAllFiles() {
 	const confirm = await os.confirm({
 		type: "warning",