diff --git a/tests/test_context_aggregators_universal.py b/tests/test_context_aggregators_universal.py
index 94acf383a..6aa38d362 100644
--- a/tests/test_context_aggregators_universal.py
+++ b/tests/test_context_aggregators_universal.py
@@ -13,10 +13,17 @@ from pipecat.frames.frames import (
     FunctionCallResultFrame,
     FunctionCallsStartedFrame,
     InterruptionFrame,
+    LLMContextAssistantTimestampFrame,
     LLMContextFrame,
+    LLMFullResponseEndFrame,
+    LLMFullResponseStartFrame,
     LLMMessagesAppendFrame,
     LLMMessagesUpdateFrame,
     LLMRunFrame,
+    LLMTextFrame,
+    LLMThoughtEndFrame,
+    LLMThoughtStartFrame,
+    LLMThoughtTextFrame,
     TranscriptionFrame,
     UserStartedSpeakingFrame,
     UserStoppedSpeakingFrame,
@@ -26,6 +33,9 @@ from pipecat.frames.frames import (
 from pipecat.pipeline.pipeline import Pipeline
 from pipecat.processors.aggregators.llm_context import LLMContext
 from pipecat.processors.aggregators.llm_response_universal import (
+    AssistantThoughtMessage,
+    AssistantTurnStoppedMessage,
+    LLMAssistantAggregator,
     LLMUserAggregator,
     LLMUserAggregatorParams,
 )
@@ -333,3 +343,172 @@ class TestLLMUserAggregator(unittest.IsolatedAsyncioTestCase):
 
         # The user mute strategies should have muted the user.
         self.assertFalse(user_turn)
+
+
+class TestLLMAssistantAggregator(unittest.IsolatedAsyncioTestCase):
+    async def test_empty(self):
+        context = LLMContext()
+
+        aggregator = LLMAssistantAggregator(context)
+
+        should_start = None
+        should_stop = None
+        stop_message = None
+
+        @aggregator.event_handler("on_assistant_turn_started")
+        async def on_assistant_turn_started(aggregator):
+            nonlocal should_start
+            should_start = True
+
+        @aggregator.event_handler("on_assistant_turn_stopped")
+        async def on_assistant_turn_stopped(aggregator, message: AssistantTurnStoppedMessage):
+            nonlocal should_stop, stop_message
+            should_stop = True
+            stop_message = message
+
+        frames_to_send = [LLMFullResponseStartFrame(), LLMFullResponseEndFrame()]
+        await run_test(aggregator, frames_to_send=frames_to_send)
+        self.assertTrue(should_start)
+        self.assertIsNone(should_stop)
+        self.assertIsNone(stop_message)
+
+    async def test_simple(self):
+        context = LLMContext()
+
+        aggregator = LLMAssistantAggregator(context)
+
+        should_start = None
+        should_stop = None
+        stop_message = None
+
+        @aggregator.event_handler("on_assistant_turn_started")
+        async def on_assistant_turn_started(aggregator):
+            nonlocal should_start
+            should_start = True
+
+        @aggregator.event_handler("on_assistant_turn_stopped")
+        async def on_assistant_turn_stopped(aggregator, message: AssistantTurnStoppedMessage):
+            nonlocal should_stop, stop_message
+            should_stop = True
+            stop_message = message
+
+        frames_to_send = [
+            LLMFullResponseStartFrame(),
+            LLMTextFrame("Hello from Pipecat!"),
+            LLMFullResponseEndFrame(),
+        ]
+        expected_down_frames = [LLMContextFrame, LLMContextAssistantTimestampFrame]
+        await run_test(
+            aggregator,
+            frames_to_send=frames_to_send,
+            expected_down_frames=expected_down_frames,
+        )
+        self.assertTrue(should_start)
+        self.assertTrue(should_stop)
+        self.assertEqual(stop_message.content, "Hello from Pipecat!")
+
+    async def test_multiple(self):
+        context = LLMContext()
+
+        aggregator = LLMAssistantAggregator(context)
+
+        should_start = None
+        should_stop = None
+        stop_message = None
+
+        @aggregator.event_handler("on_assistant_turn_started")
+        async def on_assistant_turn_started(aggregator):
+            nonlocal should_start
+            should_start = True
+
+        @aggregator.event_handler("on_assistant_turn_stopped")
+        async def on_assistant_turn_stopped(aggregator, message: AssistantTurnStoppedMessage):
+            nonlocal should_stop, stop_message
+            should_stop = True
+            stop_message = message
+
+        frames_to_send = [
+            LLMFullResponseStartFrame(),
+            LLMTextFrame("Hello "),
+            LLMTextFrame("from "),
+            LLMTextFrame("Pipecat!"),
+            LLMFullResponseEndFrame(),
+        ]
+        expected_down_frames = [LLMContextFrame, LLMContextAssistantTimestampFrame]
+        await run_test(
+            aggregator,
+            frames_to_send=frames_to_send,
+            expected_down_frames=expected_down_frames,
+        )
+        self.assertTrue(should_start)
+        self.assertTrue(should_stop)
+        self.assertEqual(stop_message.content, "Hello from Pipecat!")
+
+    async def test_interruption(self):
+        context = LLMContext()
+
+        aggregator = LLMAssistantAggregator(context)
+
+        should_start = 0
+        should_stop = 0
+        stop_messages = []
+
+        @aggregator.event_handler("on_assistant_turn_started")
+        async def on_assistant_turn_started(aggregator):
+            nonlocal should_start
+            should_start += 1
+
+        @aggregator.event_handler("on_assistant_turn_stopped")
+        async def on_assistant_turn_stopped(aggregator, message: AssistantTurnStoppedMessage):
+            nonlocal should_stop, stop_messages
+            should_stop += 1
+            stop_messages.append(message)
+
+        frames_to_send = [
+            LLMFullResponseStartFrame(),
+            LLMTextFrame("Hello "),
+            SleepFrame(),
+            InterruptionFrame(),
+            LLMFullResponseStartFrame(),
+            LLMTextFrame("Hello "),
+            LLMTextFrame("there!"),
+            LLMFullResponseEndFrame(),
+        ]
+        expected_down_frames = [
+            LLMContextFrame,
+            LLMContextAssistantTimestampFrame,
+            InterruptionFrame,
+            LLMContextFrame,
+            LLMContextAssistantTimestampFrame,
+        ]
+        await run_test(
+            aggregator,
+            frames_to_send=frames_to_send,
+            expected_down_frames=expected_down_frames,
+        )
+        self.assertEqual(should_start, 2)
+        self.assertEqual(should_stop, 2)
+        self.assertEqual(stop_messages[0].content, "Hello")
+        self.assertEqual(stop_messages[1].content, "Hello there!")
+
+    async def test_thought(self):
+        context = LLMContext()
+
+        aggregator = LLMAssistantAggregator(context)
+
+        thought_message = None
+
+        @aggregator.event_handler("on_assistant_thought")
+        async def on_assistant_thought(aggregator, message: AssistantThoughtMessage):
+            nonlocal thought_message
+            thought_message = message
+
+        frames_to_send = [
+            LLMFullResponseStartFrame(),
+            LLMThoughtStartFrame(),
+            LLMThoughtTextFrame(text="I'm thinking!"),
+            LLMThoughtEndFrame(),
+            LLMFullResponseEndFrame(),
+        ]
+        await run_test(aggregator, frames_to_send=frames_to_send)
+        self.assertEqual(thought_message.content, "I'm thinking!")