diff --git a/gateway/platforms/base.py b/gateway/platforms/base.py
index 273251385..8cb4f7c0e 100644
--- a/gateway/platforms/base.py
+++ b/gateway/platforms/base.py
@@ -1025,7 +1025,20 @@ class BasePlatformAdapter(ABC):
         self._post_delivery_callbacks: Dict[str, Any] = {}
         self._expected_cancelled_tasks: set[asyncio.Task] = set()
         self._busy_session_handler: Optional[Callable[[MessageEvent, str], Awaitable[bool]]] = None
-        # Chats where auto-TTS on voice input is disabled (set by /voice off)
+        # Auto-TTS on voice input: ``_auto_tts_default`` is the global default
+        # (``voice.auto_tts`` in config.yaml, pushed by GatewayRunner on connect).
+        # Per-chat overrides live in two sets populated from ``_voice_mode``:
+        #   - ``_auto_tts_enabled_chats``: chat explicitly opted in via ``/voice on``
+        #     or ``/voice tts`` (mode is ``voice_only`` or ``all``). Fires even when
+        #     the global default is False.
+        #   - ``_auto_tts_disabled_chats``: chat explicitly opted out via
+        #     ``/voice off`` (mode is ``off``). Suppresses auto-TTS even when the
+        #     global default is True.
+        # The gate in _process_message() is:
+        #   fire if chat in _auto_tts_enabled_chats
+        #     OR (_auto_tts_default and chat not in _auto_tts_disabled_chats)
+        self._auto_tts_default: bool = False
+        self._auto_tts_enabled_chats: set = set()
         self._auto_tts_disabled_chats: set = set()
         # Chats where typing indicator is paused (e.g. during approval waits).
         # _keep_typing skips send_typing when the chat_id is in this set.
@@ -1047,6 +1060,21 @@ class BasePlatformAdapter(ABC):
     def fatal_error_retryable(self) -> bool:
         return self._fatal_error_retryable
 
+    def _should_auto_tts_for_chat(self, chat_id: str) -> bool:
+        """Whether auto-TTS on voice input should fire for ``chat_id``.
+
+        Decision layers (Issue #16007):
+          1. Explicit ``/voice on`` or ``/voice tts`` → always fire (even if
+             ``voice.auto_tts`` is False).
+          2. Explicit ``/voice off`` → never fire.
+          3. Fall back to the global ``voice.auto_tts`` config default.
+        """
+        if chat_id in self._auto_tts_enabled_chats:
+            return True
+        if chat_id in self._auto_tts_disabled_chats:
+            return False
+        return bool(self._auto_tts_default)
+
     def set_fatal_error_handler(self, handler: Callable[["BasePlatformAdapter"], Awaitable[None] | None]) -> None:
         self._fatal_error_handler = handler
 
@@ -2214,12 +2242,14 @@ class BasePlatformAdapter(ABC):
                     logger.info("[%s] extract_local_files found %d file(s) in response", self.name, len(local_files))
                 
                 # Auto-TTS: if voice message, generate audio FIRST (before sending text)
-                # Skipped when the chat has voice mode disabled (/voice off)
+                # Gated via ``_should_auto_tts_for_chat``: fires when the chat has
+                # an explicit ``/voice on|tts`` opt-in OR when ``voice.auto_tts`` is
+                # True globally and no ``/voice off`` has been issued.
                 _tts_path = None
-                if (event.message_type == MessageType.VOICE
+                if (self._should_auto_tts_for_chat(event.source.chat_id)
+                        and event.message_type == MessageType.VOICE
                         and text_content
-                        and not media_files
-                        and event.source.chat_id not in self._auto_tts_disabled_chats):
+                        and not media_files):
                     try:
                         from tools.tts_tool import text_to_speech_tool, check_tts_requirements
                         if check_tts_requirements():
diff --git a/gateway/run.py b/gateway/run.py
index f1aafcdf3..497d9241c 100644
--- a/gateway/run.py
+++ b/gateway/run.py
@@ -881,23 +881,74 @@ class GatewayRunner:
             return
         if disabled:
             disabled_chats.add(chat_id)
+            # ``/voice off`` also clears any explicit enable — it's a hard override.
+            enabled_chats = getattr(adapter, "_auto_tts_enabled_chats", None)
+            if isinstance(enabled_chats, set):
+                enabled_chats.discard(chat_id)
         else:
             disabled_chats.discard(chat_id)
 
-    def _sync_voice_mode_state_to_adapter(self, adapter) -> None:
-        """Restore persisted /voice off state into a live platform adapter."""
-        disabled_chats = getattr(adapter, "_auto_tts_disabled_chats", None)
-        if not isinstance(disabled_chats, set):
+    def _set_adapter_auto_tts_enabled(self, adapter, chat_id: str, enabled: bool) -> None:
+        """Update an adapter's per-chat auto-TTS opt-in set if present.
+
+        Used for ``/voice on``/``/voice tts`` where the user explicitly wants
+        auto-TTS even when ``voice.auto_tts`` is False globally.
+        """
+        enabled_chats = getattr(adapter, "_auto_tts_enabled_chats", None)
+        if not isinstance(enabled_chats, set):
             return
+        if enabled:
+            enabled_chats.add(chat_id)
+            # An explicit opt-in clears any stale /voice off for this chat.
+            disabled_chats = getattr(adapter, "_auto_tts_disabled_chats", None)
+            if isinstance(disabled_chats, set):
+                disabled_chats.discard(chat_id)
+        else:
+            enabled_chats.discard(chat_id)
+
+    def _sync_voice_mode_state_to_adapter(self, adapter) -> None:
+        """Restore persisted /voice state into a live platform adapter.
+
+        Populates three fields from config + ``self._voice_mode``:
+          - ``_auto_tts_default``: global default from ``voice.auto_tts``
+          - ``_auto_tts_enabled_chats``: chats with mode ``voice_only``/``all``
+          - ``_auto_tts_disabled_chats``: chats with mode ``off``
+        """
         platform = getattr(adapter, "platform", None)
         if not isinstance(platform, Platform):
             return
-        disabled_chats.clear()
+
+        disabled_chats = getattr(adapter, "_auto_tts_disabled_chats", None)
+        enabled_chats = getattr(adapter, "_auto_tts_enabled_chats", None)
+        if not isinstance(disabled_chats, set) and not isinstance(enabled_chats, set):
+            return
+
+        # Push the global voice.auto_tts default (config.yaml) onto the adapter.
+        # Lazy import to avoid adding a module-level dep from gateway → hermes_cli.
+        try:
+            from hermes_cli.config import load_config as _load_full_config
+            _full_cfg = _load_full_config()
+            _auto_tts_default = bool(
+                (_full_cfg.get("voice") or {}).get("auto_tts", False)
+            )
+        except Exception:
+            _auto_tts_default = False
+        if hasattr(adapter, "_auto_tts_default"):
+            adapter._auto_tts_default = _auto_tts_default
+
         prefix = f"{platform.value}:"
-        disabled_chats.update(
-            key[len(prefix):] for key, mode in self._voice_mode.items()
-            if mode == "off" and key.startswith(prefix)
-        )
+        if isinstance(disabled_chats, set):
+            disabled_chats.clear()
+            disabled_chats.update(
+                key[len(prefix):] for key, mode in self._voice_mode.items()
+                if mode == "off" and key.startswith(prefix)
+            )
+        if isinstance(enabled_chats, set):
+            enabled_chats.clear()
+            enabled_chats.update(
+                key[len(prefix):] for key, mode in self._voice_mode.items()
+                if mode in ("voice_only", "all") and key.startswith(prefix)
+            )
 
     async def _safe_adapter_disconnect(self, adapter, platform) -> None:
         """Call adapter.disconnect() defensively, swallowing any error.
@@ -5977,7 +6028,7 @@ class GatewayRunner:
             self._voice_mode[voice_key] = "voice_only"
             self._save_voice_modes()
             if adapter:
-                self._set_adapter_auto_tts_disabled(adapter, chat_id, disabled=False)
+                self._set_adapter_auto_tts_enabled(adapter, chat_id, enabled=True)
             return (
                 "Voice mode enabled.\n"
                 "I'll reply with voice when you send voice messages.\n"
@@ -5993,7 +6044,7 @@ class GatewayRunner:
             self._voice_mode[voice_key] = "all"
             self._save_voice_modes()
             if adapter:
-                self._set_adapter_auto_tts_disabled(adapter, chat_id, disabled=False)
+                self._set_adapter_auto_tts_enabled(adapter, chat_id, enabled=True)
             return (
                 "Auto-TTS enabled.\n"
                 "All replies will include a voice message."
@@ -6032,7 +6083,7 @@ class GatewayRunner:
                 self._voice_mode[voice_key] = "voice_only"
                 self._save_voice_modes()
                 if adapter:
-                    self._set_adapter_auto_tts_disabled(adapter, chat_id, disabled=False)
+                    self._set_adapter_auto_tts_enabled(adapter, chat_id, enabled=True)
                 return "Voice mode enabled."
             else:
                 self._voice_mode[voice_key] = "off"
@@ -6083,7 +6134,7 @@ class GatewayRunner:
                 adapter._voice_sources[guild_id] = event.source.to_dict()
             self._voice_mode[self._voice_key(event.source.platform, event.source.chat_id)] = "all"
             self._save_voice_modes()
-            self._set_adapter_auto_tts_disabled(adapter, event.source.chat_id, disabled=False)
+            self._set_adapter_auto_tts_enabled(adapter, event.source.chat_id, enabled=True)
             return (
                 f"Joined voice channel **{voice_channel.name}**.\n"
                 f"I'll speak my replies and listen to you. Use /voice leave to disconnect."
diff --git a/tests/gateway/test_voice_command.py b/tests/gateway/test_voice_command.py
index ed36b976e..2e9c54608 100644
--- a/tests/gateway/test_voice_command.py
+++ b/tests/gateway/test_voice_command.py
@@ -177,6 +177,53 @@ class TestHandleVoiceCommand:
 
         assert adapter._auto_tts_disabled_chats == {"123"}
 
+    def test_sync_populates_enabled_chats_from_voice_modes(self, runner):
+        """Issue #16007: sync also restores per-chat /voice on|tts opt-ins.
+
+        The adapter's ``_auto_tts_enabled_chats`` must mirror chats whose
+        persisted voice_mode is ``voice_only`` or ``all`` — without this,
+        ``/voice on`` was relying on a "not in disabled set" default that
+        silently enabled auto-TTS for every chat.
+        """
+        from gateway.config import Platform
+        runner._voice_mode = {
+            "telegram:off_chat": "off",
+            "telegram:on_chat": "voice_only",
+            "telegram:tts_chat": "all",
+            "slack:999": "voice_only",  # wrong platform, must be ignored
+        }
+        adapter = SimpleNamespace(
+            _auto_tts_default=False,
+            _auto_tts_disabled_chats=set(),
+            _auto_tts_enabled_chats=set(),
+            platform=Platform.TELEGRAM,
+        )
+
+        runner._sync_voice_mode_state_to_adapter(adapter)
+
+        assert adapter._auto_tts_disabled_chats == {"off_chat"}
+        assert adapter._auto_tts_enabled_chats == {"on_chat", "tts_chat"}
+
+    def test_sync_pushes_config_default_onto_adapter(self, runner, monkeypatch):
+        """Issue #16007: ``voice.auto_tts`` must propagate to ``_auto_tts_default``."""
+        from gateway.config import Platform
+
+        fake_cfg = {"voice": {"auto_tts": True}}
+        monkeypatch.setattr(
+            "hermes_cli.config.load_config",
+            lambda: fake_cfg,
+        )
+        adapter = SimpleNamespace(
+            _auto_tts_default=False,
+            _auto_tts_disabled_chats=set(),
+            _auto_tts_enabled_chats=set(),
+            platform=Platform.TELEGRAM,
+        )
+
+        runner._sync_voice_mode_state_to_adapter(adapter)
+
+        assert adapter._auto_tts_default is True
+
     def test_restart_restores_voice_off_state(self, runner, tmp_path):
         from gateway.config import Platform
         runner._VOICE_MODE_PATH.write_text(json.dumps({"telegram:123": "off"}))
@@ -2706,3 +2753,56 @@ class TestUDPKeepalive:
             mock_conn.send_packet.assert_called_with(b'\xf8\xff\xfe')
         finally:
             DiscordAdapter._KEEPALIVE_INTERVAL = original_interval
+
+
+# =====================================================================
+# BasePlatformAdapter._should_auto_tts_for_chat — gate for auto-TTS
+# on voice input. Regression test for Issue #16007.
+# =====================================================================
+
+class TestShouldAutoTtsForChat:
+    """Three-layer gate: per-chat enable > per-chat disable > config default."""
+
+    def _make_adapter(self, *, default: bool, enabled=(), disabled=()):
+        """Build a bare adapter with only the attrs the gate reads."""
+        adapter = SimpleNamespace(
+            _auto_tts_default=default,
+            _auto_tts_enabled_chats=set(enabled),
+            _auto_tts_disabled_chats=set(disabled),
+        )
+        # Bind the unbound method — _should_auto_tts_for_chat only reads the
+        # three attrs above via ``self.``, so an unbound call works.
+        from gateway.platforms.base import BasePlatformAdapter
+        return BasePlatformAdapter._should_auto_tts_for_chat, adapter
+
+    def test_default_false_no_override_suppresses(self):
+        """Issue #16007: voice.auto_tts=False and no per-chat state → no TTS."""
+        fn, adapter = self._make_adapter(default=False)
+        assert fn(adapter, "chat1") is False
+
+    def test_default_true_no_override_fires(self):
+        fn, adapter = self._make_adapter(default=True)
+        assert fn(adapter, "chat1") is True
+
+    def test_explicit_enable_overrides_false_default(self):
+        """``/voice on`` with config auto_tts=False still fires."""
+        fn, adapter = self._make_adapter(default=False, enabled={"chat1"})
+        assert fn(adapter, "chat1") is True
+
+    def test_explicit_disable_overrides_true_default(self):
+        """``/voice off`` with config auto_tts=True still suppresses."""
+        fn, adapter = self._make_adapter(default=True, disabled={"chat1"})
+        assert fn(adapter, "chat1") is False
+
+    def test_enabled_wins_over_disabled(self):
+        """An explicit enable beats an explicit disable (enable takes priority)."""
+        fn, adapter = self._make_adapter(
+            default=False, enabled={"chat1"}, disabled={"chat1"}
+        )
+        assert fn(adapter, "chat1") is True
+
+    def test_per_chat_isolation(self):
+        """Enable for chat1 doesn't leak to chat2."""
+        fn, adapter = self._make_adapter(default=False, enabled={"chat1"})
+        assert fn(adapter, "chat1") is True
+        assert fn(adapter, "chat2") is False