diff --git a/.env.example b/.env.example
index f7793ed23..909bba5c1 100644
--- a/.env.example
+++ b/.env.example
@@ -27,8 +27,8 @@ VITE_STATIC_ASSETS_URL=https://sendou-assets.nyc3.cdn.digitaloceanspaces.com
 TWITCH_CLIENT_ID=
 TWITCH_CLIENT_SECRET=
 
-// Discord webhook new user reports are posted to (skipped when unset)
-USER_REPORT_DISCORD_WEBHOOK_URL=
+// Discord webhook mod events (user reports, bans) are posted to (skipped when unset)
+MOD_DISCORD_WEBHOOK_URL=
 
 SKALOP_SYSTEM_MESSAGE_URL=http://localhost:5900/system
 SKALOP_TOKEN=secret
diff --git a/app/features/admin/actions/admin.server.ts b/app/features/admin/actions/admin.server.ts
index be285ae14..70bb5a74e 100644
--- a/app/features/admin/actions/admin.server.ts
+++ b/app/features/admin/actions/admin.server.ts
@@ -8,12 +8,17 @@ import * as UserRepository from "~/features/user-page/UserRepository.server";
 import { requireRole } from "~/modules/permissions/guards.server";
 import {
 	errorToast,
+	notFoundIfFalsy,
 	parseRequestPayload,
 	successToast,
 } from "~/utils/remix.server";
 import { errorIsSqliteForeignKeyConstraintFailure } from "~/utils/sql";
 import { assertUnreachable } from "~/utils/types";
 import { _action, actualNumber, friendCode } from "~/utils/zod";
+import {
+	sendUserBannedWebhook,
+	sendUserUnbannedWebhook,
+} from "../core/discord-webhook.server";
 import { plusTiersFromVotingAndLeaderboard } from "../core/plus-tier.server";
 
 export const action = async ({ request }: ActionFunctionArgs) => {
@@ -124,21 +129,37 @@ export const action = async ({ request }: ActionFunctionArgs) => {
 		case "BAN_USER": {
 			requireRole("STAFF");
 
+			const bannedUser = notFoundIfFalsy(
+				await UserRepository.findLeanById(data.user),
+			);
+			const banExpiresAt = data.duration ? new Date(data.duration) : null;
+
 			await AdminRepository.banUser({
 				bannedReason: data.reason ?? null,
 				userId: data.user,
-				banned: data.duration ? new Date(data.duration) : 1,
+				banned: banExpiresAt ?? 1,
 				bannedByUserId: user.id,
 			});
 
 			await refreshBannedCache();
 
+			sendUserBannedWebhook({
+				bannedUser,
+				bannedBy: user,
+				reason: data.reason ?? null,
+				expiresAt: banExpiresAt,
+			});
+
 			message = "User banned";
 			break;
 		}
 		case "UNBAN_USER": {
 			requireRole("STAFF");
 
+			const unbannedUser = notFoundIfFalsy(
+				await UserRepository.findLeanById(data.user),
+			);
+
 			await AdminRepository.unbanUser({
 				userId: data.user,
 				unbannedByUserId: user.id,
@@ -146,6 +167,11 @@ export const action = async ({ request }: ActionFunctionArgs) => {
 
 			await refreshBannedCache();
 
+			sendUserUnbannedWebhook({
+				unbannedUser,
+				unbannedBy: user,
+			});
+
 			message = "User unbanned";
 			break;
 		}
diff --git a/app/features/admin/core/discord-webhook.server.ts b/app/features/admin/core/discord-webhook.server.ts
new file mode 100644
index 000000000..b1ecaeaf2
--- /dev/null
+++ b/app/features/admin/core/discord-webhook.server.ts
@@ -0,0 +1,70 @@
+import {
+	sendModDiscordWebhook,
+	truncateEmbedValue,
+	userAdminPageLink,
+	userPageLink,
+	type WebhookUser,
+} from "~/modules/discord-webhook.server";
+
+/**
+ * Posts a rich embed about a user getting banned to the mod channel Discord webhook.
+ * Fire-and-forget (see `sendModDiscordWebhook`).
+ */
+export function sendUserBannedWebhook(args: {
+	bannedUser: WebhookUser;
+	bannedBy: WebhookUser;
+	reason: string | null;
+	/** When the ban ends, null when the ban has no end date */
+	expiresAt: Date | null;
+}) {
+	sendModDiscordWebhook({
+		title: "User banned",
+		fields: [
+			{
+				name: "Banned user",
+				value: userAdminPageLink(args.bannedUser),
+			},
+			{
+				name: "Banned by",
+				value: userPageLink(args.bannedBy),
+			},
+			{
+				name: "Expires",
+				value: args.expiresAt
+					? `<t:${Math.floor(args.expiresAt.getTime() / 1000)}:f>`
+					: "No end date",
+			},
+			...(args.reason
+				? [
+						{
+							name: "Reason",
+							value: truncateEmbedValue(args.reason),
+						},
+					]
+				: []),
+		],
+	});
+}
+
+/**
+ * Posts a rich embed about a user getting unbanned to the mod channel Discord webhook.
+ * Fire-and-forget (see `sendModDiscordWebhook`).
+ */
+export function sendUserUnbannedWebhook(args: {
+	unbannedUser: WebhookUser;
+	unbannedBy: WebhookUser;
+}) {
+	sendModDiscordWebhook({
+		title: "User unbanned",
+		fields: [
+			{
+				name: "Unbanned user",
+				value: userAdminPageLink(args.unbannedUser),
+			},
+			{
+				name: "Unbanned by",
+				value: userPageLink(args.unbannedBy),
+			},
+		],
+	});
+}
diff --git a/app/features/user-report/core/discord-webhook.server.ts b/app/features/user-report/core/discord-webhook.server.ts
index d003db9bc..cacc3f5d6 100644
--- a/app/features/user-report/core/discord-webhook.server.ts
+++ b/app/features/user-report/core/discord-webhook.server.ts
@@ -1,93 +1,58 @@
 import type { UserReportCategory } from "~/db/tables";
-import { logger } from "~/utils/logger";
-import { SENDOU_INK_BASE_URL, sendouQMatchPage, userPage } from "~/utils/urls";
+import {
+	sendModDiscordWebhook,
+	truncateEmbedValue,
+	userAdminPageLink,
+	userPageLink,
+	type WebhookUser,
+} from "~/modules/discord-webhook.server";
+import { SENDOU_INK_BASE_URL, sendouQMatchPage } from "~/utils/urls";
 import { USER_REPORT_CATEGORY_LABELS } from "../user-report-constants";
 
-const EMBED_DESCRIPTION_MAX_LENGTH = 1000;
-
 /**
  * Posts a rich embed about a new/updated user report to the mod channel Discord webhook.
- * Fire-and-forget: meant to be called without awaiting, never throws, skipped with a log
- * line when `USER_REPORT_DISCORD_WEBHOOK_URL` is unset (e.g. in development).
+ * Fire-and-forget (see `sendModDiscordWebhook`).
  */
 export function sendUserReportWebhook(args: {
-	reportedUser: { id: number; username: string };
-	reporter: { username: string; discordId: string; customUrl: string | null };
+	reportedUser: WebhookUser;
+	reporter: WebhookUser;
 	category: UserReportCategory;
 	description: string;
 	matchId: number | null;
 	isUpdate: boolean;
 	reportCounts: { lastMonth: number; lastYear: number };
 }) {
-	const webhookUrl = process.env.USER_REPORT_DISCORD_WEBHOOK_URL;
-	if (!webhookUrl) {
-		logger.info(
-			"USER_REPORT_DISCORD_WEBHOOK_URL not set, skipping user report webhook",
-		);
-		return;
-	}
-
-	const reportedUserAdminUrl = `${SENDOU_INK_BASE_URL}/u/${args.reportedUser.id}/admin`;
-	const reporterUrl = `${SENDOU_INK_BASE_URL}${userPage(args.reporter)}`;
-
-	const body = {
-		embeds: [
+	sendModDiscordWebhook({
+		title: args.isUpdate ? "User report updated" : "New user report",
+		fields: [
 			{
-				title: args.isUpdate ? "User report updated" : "New user report",
-				fields: [
-					{
-						name: "Reported user",
-						value: `[${args.reportedUser.username}](${reportedUserAdminUrl})`,
-					},
-					{
-						name: "Reporter",
-						value: `[${args.reporter.username}](${reporterUrl})`,
-					},
-					{
-						name: "Category",
-						value: USER_REPORT_CATEGORY_LABELS[args.category],
-					},
-					{
-						name: "Description",
-						value: truncate(args.description),
-					},
-					...(args.matchId !== null
-						? [
-								{
-									name: "SendouQ match",
-									value: `[#${args.matchId}](${SENDOU_INK_BASE_URL}${sendouQMatchPage(args.matchId)})`,
-								},
-							]
-						: []),
-					{
-						name: "Reports against this user",
-						value: `Last month: ${args.reportCounts.lastMonth} • Last year: ${args.reportCounts.lastYear}`,
-					},
-				],
-				timestamp: new Date().toISOString(),
+				name: "Reported user",
+				value: userAdminPageLink(args.reportedUser),
+			},
+			{
+				name: "Reporter",
+				value: userPageLink(args.reporter),
+			},
+			{
+				name: "Category",
+				value: USER_REPORT_CATEGORY_LABELS[args.category],
+			},
+			{
+				name: "Description",
+				value: truncateEmbedValue(args.description),
+			},
+			...(args.matchId !== null
+				? [
+						{
+							name: "SendouQ match",
+							value: `[#${args.matchId}](${SENDOU_INK_BASE_URL}${sendouQMatchPage(args.matchId)})`,
+						},
+					]
+				: []),
+			{
+				name: "Reports against this user",
+				value: `Last month: ${args.reportCounts.lastMonth} • Last year: ${args.reportCounts.lastYear}`,
 			},
 		],
-	};
-
-	fetch(webhookUrl, {
-		method: "POST",
-		headers: { "Content-Type": "application/json" },
-		body: JSON.stringify(body),
-	})
-		.then((response) => {
-			if (!response.ok) {
-				logger.error(
-					`User report webhook responded with status ${response.status}`,
-				);
-			}
-		})
-		.catch((error) => {
-			logger.error("Failed to send user report webhook", error);
-		});
-}
-
-function truncate(description: string) {
-	if (description.length <= EMBED_DESCRIPTION_MAX_LENGTH) return description;
-
-	return `${description.slice(0, EMBED_DESCRIPTION_MAX_LENGTH)}…`;
+	});
 }
diff --git a/app/modules/discord-webhook.server.ts b/app/modules/discord-webhook.server.ts
new file mode 100644
index 000000000..690a19816
--- /dev/null
+++ b/app/modules/discord-webhook.server.ts
@@ -0,0 +1,77 @@
+import { logger } from "~/utils/logger";
+import { SENDOU_INK_BASE_URL, userAdminPage, userPage } from "~/utils/urls";
+
+const EMBED_FIELD_VALUE_MAX_LENGTH = 1000;
+
+interface ModWebhookEmbed {
+	title: string;
+	fields: Array<{ name: string; value: string }>;
+}
+
+export interface WebhookUser {
+	username: string;
+	discordId: string;
+	customUrl: string | null;
+}
+
+/**
+ * Posts a rich embed to the mod channel Discord webhook.
+ * Fire-and-forget: meant to be called without awaiting, never throws, skipped with a log
+ * line when `MOD_DISCORD_WEBHOOK_URL` is unset (e.g. in development).
+ */
+export function sendModDiscordWebhook(embed: ModWebhookEmbed) {
+	const webhookUrl = process.env.MOD_DISCORD_WEBHOOK_URL;
+	if (!webhookUrl) {
+		logger.info(
+			"MOD_DISCORD_WEBHOOK_URL not set, skipping mod Discord webhook",
+		);
+		return;
+	}
+
+	const body = {
+		embeds: [{ ...embed, timestamp: new Date().toISOString() }],
+		allowed_mentions: { parse: [] },
+	};
+
+	fetch(webhookUrl, {
+		method: "POST",
+		headers: { "Content-Type": "application/json" },
+		body: JSON.stringify(body),
+	})
+		.then((response) => {
+			if (!response.ok) {
+				logger.error(
+					`Mod Discord webhook responded with status ${response.status}`,
+				);
+			}
+		})
+		.catch((error) => {
+			logger.error("Failed to send mod Discord webhook", error);
+		});
+}
+
+/**
+ * Escapes then truncates free-text user input so it fits inside a Discord embed field
+ * value without breaking the embed's markdown formatting.
+ */
+export function truncateEmbedValue(text: string) {
+	const escaped = escapeMarkdown(text);
+	if (escaped.length <= EMBED_FIELD_VALUE_MAX_LENGTH) return escaped;
+
+	return `${escaped.slice(0, EMBED_FIELD_VALUE_MAX_LENGTH)}…`;
+}
+
+/** Markdown link to the user's admin tab (moderation actions & notes). */
+export function userAdminPageLink(user: WebhookUser) {
+	return `[${escapeMarkdown(user.username)}](${SENDOU_INK_BASE_URL}${userAdminPage(user)})`;
+}
+
+/** Markdown link to the user's profile page. */
+export function userPageLink(user: WebhookUser) {
+	return `[${escapeMarkdown(user.username)}](${SENDOU_INK_BASE_URL}${userPage(user)})`;
+}
+
+/** Backslash-escapes Discord markdown so user text can't forge links or break formatting. */
+function escapeMarkdown(text: string) {
+	return text.replace(/[\\`*_~|()[\]]/g, "\\$&");
+}