diff --git a/js/app.js b/js/app.js
index 8c4074dd..598574ca 100644
--- a/js/app.js
+++ b/js/app.js
@@ -628,6 +628,15 @@ class Application {
       this.authService.hydrateFromStorage();
       this.renderSavedProfiles();
 
+      if (
+        this.nostrService &&
+        typeof this.nostrService.setDmBlockChecker === "function"
+      ) {
+        this.nostrService.setDmBlockChecker((pubkey) =>
+          this.isAuthorBlocked(pubkey),
+        );
+      }
+
       loadModerationOverridesFromStorage();
       loadModerationSettingsFromStorage();
       loadDmPrivacySettingsFromStorage();
diff --git a/js/services/nostrService.js b/js/services/nostrService.js
index 9170378f..ea2fb0c7 100644
--- a/js/services/nostrService.js
+++ b/js/services/nostrService.js
@@ -635,6 +635,7 @@ export class NostrService {
       logger: userLogger,
     });
     this.dmPreviewCache = new LRUCache({ maxSize: DM_PREVIEW_CACHE_LIMIT });
+    this._dmBlockChecker = null;
     try {
       if (this.moderationService && typeof this.moderationService.setNostrClient === "function") {
         this.moderationService.setNostrClient(this.nostrClient);
@@ -644,6 +645,28 @@ export class NostrService {
     }
   }
 
+  setDmBlockChecker(checker) {
+    this._dmBlockChecker =
+      typeof checker === "function" ? checker : null;
+  }
+
+  _isDmRemoteBlocked(message, actorPubkey) {
+    if (typeof this._dmBlockChecker !== "function") {
+      return false;
+    }
+    try {
+      const actor = normalizeHexPubkey(actorPubkey || this.dmActorPubkey || "");
+      const remote = resolveDirectMessageRemotePubkey(message, actor);
+      if (!remote) {
+        return false;
+      }
+      return this._dmBlockChecker(remote);
+    } catch (error) {
+      devLogger.warn("[nostrService] Block check failed for DM", error);
+      return false;
+    }
+  }
+
   log(...args) {
     try {
       this.logger(...args);
@@ -810,6 +833,13 @@ export class NostrService {
       return null;
     }
 
+    if (this._isDmRemoteBlocked(message, actorPubkey)) {
+      devLogger.log("[nostrService] Skipping persist for blocked DM sender", {
+        id: record.id,
+      });
+      return null;
+    }
+
     try {
       await writeMessages(record);
       const notificationResult = await this.dmNotificationManager.recordMessage({
@@ -876,6 +906,11 @@ export class NostrService {
       return;
     }
 
+    if (this._isDmRemoteBlocked(normalized)) {
+      devLogger.log("[nostrService] Dropping DM from blocked user", { eventId });
+      return;
+    }
+
     this.dmMessageIndex.set(eventId, normalized);
 
     const actor = normalizeHexPubkey(
diff --git a/js/ui/applicationBootstrap.js b/js/ui/applicationBootstrap.js
index 88e847cf..15e75d05 100644
--- a/js/ui/applicationBootstrap.js
+++ b/js/ui/applicationBootstrap.js
@@ -798,8 +798,28 @@ export default class ApplicationBootstrap {
       try {
         const summaries =
           await app.nostrService.listDirectMessageConversationSummaries();
+        const actorHex =
+          typeof app.normalizeHexPubkey === "function" && app.pubkey
+            ? app.normalizeHexPubkey(app.pubkey)
+            : "";
+        const canCheckBlock =
+          userBlocks && typeof userBlocks.isBlocked === "function";
         const totalUnseen = Array.isArray(summaries)
           ? summaries.reduce((sum, summary) => {
+              if (canCheckBlock && actorHex && summary?.conversation_id) {
+                const parts = summary.conversation_id.split(":");
+                const remote =
+                  parts.length === 3 && parts[0] === "dm"
+                    ? parts[1] === actorHex
+                      ? parts[2]
+                      : parts[2] === actorHex
+                        ? parts[1]
+                        : ""
+                    : "";
+                if (remote && userBlocks.isBlocked(remote)) {
+                  return sum;
+                }
+              }
               const count = Number(summary?.unseen_count);
               return sum + (Number.isFinite(count) ? count : 0);
             }, 0)
diff --git a/js/ui/profileModalController.js b/js/ui/profileModalController.js
index cc07eebf..2ff1bdd4 100644
--- a/js/ui/profileModalController.js
+++ b/js/ui/profileModalController.js
@@ -4197,7 +4197,15 @@ export class ProfileModalController {
       };
     }
 
-    const threads = this.groupDirectMessages(messages, actor);
+    const allThreads = this.groupDirectMessages(messages, actor);
+    const blocksService = this.services.userBlocks;
+    const isRemoteBlocked =
+      blocksService && typeof blocksService.isBlocked === "function"
+        ? (pubkey) => blocksService.isBlocked(pubkey)
+        : () => false;
+    const threads = allThreads.filter(
+      (thread) => !thread.remoteHex || !isRemoteBlocked(thread.remoteHex),
+    );
     const remoteKeys = new Set();
     threads.forEach((thread) => {
       if (thread.remoteHex) {
diff --git a/tests/dm-block-filter.test.mjs b/tests/dm-block-filter.test.mjs
new file mode 100644
index 00000000..3ca1b276
--- /dev/null
+++ b/tests/dm-block-filter.test.mjs
@@ -0,0 +1,173 @@
+import { describe, it, beforeEach, afterEach, mock } from "node:test";
+import assert from "node:assert/strict";
+import nostrService from "../js/services/nostrService.js";
+
+const ACTOR_PUBKEY = "aaaa".repeat(16);
+const BLOCKED_PUBKEY = "bbbb".repeat(16);
+const ALLOWED_PUBKEY = "cccc".repeat(16);
+
+function makeDmMessage({ senderPubkey, receiverPubkey, eventId, direction }) {
+  return {
+    ok: true,
+    direction: direction || "incoming",
+    sender: { pubkey: senderPubkey },
+    recipients: [{ pubkey: receiverPubkey }],
+    remotePubkey:
+      direction === "outgoing" ? receiverPubkey : senderPubkey,
+    actorPubkey: direction === "outgoing" ? senderPubkey : receiverPubkey,
+    timestamp: Math.floor(Date.now() / 1000),
+    plaintext: "Hello",
+    event: {
+      id: eventId || `evt-${Math.random().toString(36).slice(2)}`,
+      kind: 4,
+      pubkey: senderPubkey,
+      created_at: Math.floor(Date.now() / 1000),
+      tags: [["p", receiverPubkey]],
+    },
+    message: {
+      kind: 4,
+      pubkey: senderPubkey,
+      tags: [["p", receiverPubkey]],
+    },
+  };
+}
+
+describe("DM block/mute filtering", () => {
+  beforeEach(() => {
+    nostrService.dmMessages = [];
+    nostrService.dmMessageIndex = new Map();
+    nostrService.dmActorPubkey = ACTOR_PUBKEY;
+    nostrService.dmHydratedFromSnapshot = false;
+  });
+
+  afterEach(() => {
+    nostrService.setDmBlockChecker(null);
+    nostrService.dmMessages = [];
+    nostrService.dmMessageIndex = new Map();
+    nostrService.dmActorPubkey = null;
+    mock.reset();
+  });
+
+  describe("setDmBlockChecker", () => {
+    it("should accept a function", () => {
+      nostrService.setDmBlockChecker(() => false);
+      assert.equal(typeof nostrService._dmBlockChecker, "function");
+    });
+
+    it("should clear checker when passed null", () => {
+      nostrService.setDmBlockChecker(() => true);
+      nostrService.setDmBlockChecker(null);
+      assert.equal(nostrService._dmBlockChecker, null);
+    });
+
+    it("should clear checker when passed non-function", () => {
+      nostrService.setDmBlockChecker(() => true);
+      nostrService.setDmBlockChecker("not-a-function");
+      assert.equal(nostrService._dmBlockChecker, null);
+    });
+  });
+
+  describe("applyDirectMessage with block checker", () => {
+    it("should drop messages from blocked senders", () => {
+      nostrService.setDmBlockChecker((pubkey) => pubkey === BLOCKED_PUBKEY);
+
+      const message = makeDmMessage({
+        senderPubkey: BLOCKED_PUBKEY,
+        receiverPubkey: ACTOR_PUBKEY,
+        eventId: "blocked-msg-1",
+        direction: "incoming",
+      });
+
+      nostrService.applyDirectMessage(message, { reason: "test" });
+
+      assert.equal(nostrService.dmMessages.length, 0);
+      assert.equal(nostrService.dmMessageIndex.has("blocked-msg-1"), false);
+    });
+
+    it("should allow messages from non-blocked senders", () => {
+      nostrService.setDmBlockChecker((pubkey) => pubkey === BLOCKED_PUBKEY);
+
+      const message = makeDmMessage({
+        senderPubkey: ALLOWED_PUBKEY,
+        receiverPubkey: ACTOR_PUBKEY,
+        eventId: "allowed-msg-1",
+        direction: "incoming",
+      });
+
+      nostrService.applyDirectMessage(message, { reason: "test" });
+
+      assert.equal(nostrService.dmMessages.length, 1);
+    });
+
+    it("should allow all messages when no block checker is set", () => {
+      const message = makeDmMessage({
+        senderPubkey: BLOCKED_PUBKEY,
+        receiverPubkey: ACTOR_PUBKEY,
+        eventId: "no-checker-msg-1",
+        direction: "incoming",
+      });
+
+      nostrService.applyDirectMessage(message, { reason: "test" });
+
+      assert.equal(nostrService.dmMessages.length, 1);
+    });
+
+    it("should block outgoing messages to blocked recipients", () => {
+      nostrService.setDmBlockChecker((pubkey) => pubkey === BLOCKED_PUBKEY);
+
+      const message = makeDmMessage({
+        senderPubkey: ACTOR_PUBKEY,
+        receiverPubkey: BLOCKED_PUBKEY,
+        eventId: "outgoing-blocked-1",
+        direction: "outgoing",
+      });
+
+      nostrService.applyDirectMessage(message, { reason: "test" });
+
+      assert.equal(nostrService.dmMessages.length, 0);
+    });
+  });
+
+  describe("_isDmRemoteBlocked", () => {
+    it("should return false when no checker is set", () => {
+      const message = makeDmMessage({
+        senderPubkey: BLOCKED_PUBKEY,
+        receiverPubkey: ACTOR_PUBKEY,
+        direction: "incoming",
+      });
+      assert.equal(nostrService._isDmRemoteBlocked(message), false);
+    });
+
+    it("should return true for blocked remote pubkey", () => {
+      nostrService.setDmBlockChecker((pubkey) => pubkey === BLOCKED_PUBKEY);
+      const message = makeDmMessage({
+        senderPubkey: BLOCKED_PUBKEY,
+        receiverPubkey: ACTOR_PUBKEY,
+        direction: "incoming",
+      });
+      assert.equal(nostrService._isDmRemoteBlocked(message), true);
+    });
+
+    it("should return false for allowed remote pubkey", () => {
+      nostrService.setDmBlockChecker((pubkey) => pubkey === BLOCKED_PUBKEY);
+      const message = makeDmMessage({
+        senderPubkey: ALLOWED_PUBKEY,
+        receiverPubkey: ACTOR_PUBKEY,
+        direction: "incoming",
+      });
+      assert.equal(nostrService._isDmRemoteBlocked(message), false);
+    });
+
+    it("should handle checker that throws", () => {
+      nostrService.setDmBlockChecker(() => {
+        throw new Error("checker error");
+      });
+      const message = makeDmMessage({
+        senderPubkey: BLOCKED_PUBKEY,
+        receiverPubkey: ACTOR_PUBKEY,
+        direction: "incoming",
+      });
+      assert.equal(nostrService._isDmRemoteBlocked(message), false);
+    });
+  });
+});