diff --git a/lib/crewai/src/crewai/utilities/agent_utils.py b/lib/crewai/src/crewai/utilities/agent_utils.py
index 48af1cf8b..22b498541 100644
--- a/lib/crewai/src/crewai/utilities/agent_utils.py
+++ b/lib/crewai/src/crewai/utilities/agent_utils.py
@@ -2,6 +2,7 @@ from __future__ import annotations
 
 import asyncio
 from collections.abc import Callable, Sequence
+import concurrent.futures
 import json
 import re
 from typing import TYPE_CHECKING, Any, Final, Literal, TypedDict
@@ -678,17 +679,22 @@ def _format_messages_for_summary(messages: list[LLMMessage]) -> str:
                 tool_names = []
                 for tc in tool_calls:
                     func = tc.get("function", {})
-                    name = func.get("name", "unknown") if isinstance(func, dict) else "unknown"
+                    name = (
+                        func.get("name", "unknown")
+                        if isinstance(func, dict)
+                        else "unknown"
+                    )
                     tool_names.append(name)
                 content = f"[Called tools: {', '.join(tool_names)}]"
             else:
                 content = ""
         elif isinstance(content, list):
             # Multimodal content blocks — extract text parts
-            text_parts = []
-            for block in content:
-                if isinstance(block, dict) and block.get("type") == "text":
-                    text_parts.append(block.get("text", ""))
+            text_parts = [
+                block.get("text", "")
+                for block in content
+                if isinstance(block, dict) and block.get("type") == "text"
+            ]
             content = " ".join(text_parts) if text_parts else "[multimodal content]"
 
         if role == "assistant":
@@ -771,6 +777,44 @@ def _extract_summary_tags(text: str) -> str:
     return text.strip()
 
 
+async def _asummarize_chunks(
+    chunks: list[list[LLMMessage]],
+    llm: LLM | BaseLLM,
+    callbacks: list[TokenCalcHandler],
+    i18n: I18N,
+) -> list[SummaryContent]:
+    """Summarize multiple message chunks concurrently using asyncio.
+
+    Args:
+        chunks: List of message chunks to summarize.
+        llm: LLM instance (must support ``acall``).
+        callbacks: List of callbacks for the LLM.
+        i18n: I18N instance for prompt templates.
+
+    Returns:
+        Ordered list of summary contents, one per chunk.
+    """
+
+    async def _summarize_one(chunk: list[LLMMessage]) -> SummaryContent:
+        conversation_text = _format_messages_for_summary(chunk)
+        summarization_messages = [
+            format_message_for_llm(
+                i18n.slice("summarizer_system_message"), role="system"
+            ),
+            format_message_for_llm(
+                i18n.slice("summarize_instruction").format(
+                    conversation=conversation_text
+                ),
+            ),
+        ]
+        summary = await llm.acall(summarization_messages, callbacks=callbacks)
+        extracted = _extract_summary_tags(str(summary))
+        return {"content": extracted}
+
+    results = await asyncio.gather(*[_summarize_one(chunk) for chunk in chunks])
+    return list(results)
+
+
 def summarize_messages(
     messages: list[LLMMessage],
     llm: LLM | BaseLLM,
@@ -813,42 +857,52 @@ def summarize_messages(
     chunks = _split_messages_into_chunks(non_system_messages, max_tokens)
 
     # 4. Summarize each chunk with role-labeled formatting
-    summarized_contents: list[SummaryContent] = []
     total_chunks = len(chunks)
 
-    for idx, chunk in enumerate(chunks, 1):
+    if total_chunks <= 1:
+        # Single chunk — no benefit from async overhead
+        summarized_contents: list[SummaryContent] = []
+        for idx, chunk in enumerate(chunks, 1):
+            if verbose:
+                Printer().print(
+                    content=f"Summarizing {idx}/{total_chunks}...",
+                    color="yellow",
+                )
+            conversation_text = _format_messages_for_summary(chunk)
+            summarization_messages = [
+                format_message_for_llm(
+                    i18n.slice("summarizer_system_message"), role="system"
+                ),
+                format_message_for_llm(
+                    i18n.slice("summarize_instruction").format(
+                        conversation=conversation_text
+                    ),
+                ),
+            ]
+            summary = llm.call(summarization_messages, callbacks=callbacks)
+            extracted = _extract_summary_tags(str(summary))
+            summarized_contents.append({"content": extracted})
+    else:
+        # Multiple chunks — summarize in parallel via asyncio
         if verbose:
             Printer().print(
-                content=f"Summarizing {idx}/{total_chunks}...",
+                content=f"Summarizing {total_chunks} chunks in parallel...",
                 color="yellow",
             )
-
-        conversation_text = _format_messages_for_summary(chunk)
-
-        summarization_messages = [
-            format_message_for_llm(
-                i18n.slice("summarizer_system_message"), role="system"
-            ),
-            format_message_for_llm(
-                i18n.slice("summarize_instruction").format(
-                    conversation=conversation_text
-                ),
-            ),
-        ]
-        summary = llm.call(
-            summarization_messages,
-            callbacks=callbacks,
+        coro = _asummarize_chunks(
+            chunks=chunks, llm=llm, callbacks=callbacks, i18n=i18n
         )
-        # Extract content from <summary> tags with graceful fallback
-        extracted = _extract_summary_tags(str(summary))
-        summarized_contents.append({"content": extracted})
+        if is_inside_event_loop():
+            with concurrent.futures.ThreadPoolExecutor(max_workers=1) as pool:
+                summarized_contents = pool.submit(asyncio.run, coro).result()
+        else:
+            summarized_contents = asyncio.run(coro)
 
     merged_summary = "\n\n".join(content["content"] for content in summarized_contents)
 
     # 6. Reconstruct messages: [system messages...] + [summary user message]
     messages.clear()
-    for sys_msg in system_messages:
-        messages.append(sys_msg)
+    messages.extend(system_messages)
 
     summary_message = format_message_for_llm(
         i18n.slice("summary").format(merged_summary=merged_summary)
diff --git a/lib/crewai/tests/utilities/test_agent_utils.py b/lib/crewai/tests/utilities/test_agent_utils.py
index 778c5c21e..31d7b9705 100644
--- a/lib/crewai/tests/utilities/test_agent_utils.py
+++ b/lib/crewai/tests/utilities/test_agent_utils.py
@@ -2,13 +2,16 @@
 
 from __future__ import annotations
 
+import asyncio
 from typing import Any
-from unittest.mock import MagicMock, patch
+from unittest.mock import AsyncMock, MagicMock, patch
 
+import pytest
 from pydantic import BaseModel, Field
 
 from crewai.tools.base_tool import BaseTool
 from crewai.utilities.agent_utils import (
+    _asummarize_chunks,
     _estimate_token_count,
     _extract_summary_tags,
     _format_messages_for_summary,
@@ -621,3 +624,301 @@ class TestEstimateTokenCount:
         estimated = _estimate_token_count(text)
         assert estimated > 0
         assert estimated == len(text) // 4
+
+
+class TestParallelSummarization:
+    """Tests for parallel chunk summarization via asyncio."""
+
+    def _make_messages_for_n_chunks(self, n: int) -> list[dict[str, Any]]:
+        """Build a message list that will produce exactly *n* chunks.
+
+        Each message has 400 chars (~100 tokens). With max_tokens=100 returned
+        by the mock LLM, each message lands in its own chunk.
+        """
+        msgs: list[dict[str, Any]] = []
+        for i in range(n):
+            msgs.append({"role": "user", "content": f"msg-{i} " + "x" * 400})
+        return msgs
+
+    def test_multiple_chunks_use_acall(self) -> None:
+        """When there are multiple chunks, summarize_messages should use
+        llm.acall (parallel) instead of llm.call (sequential)."""
+        messages = self._make_messages_for_n_chunks(3)
+
+        mock_llm = MagicMock()
+        mock_llm.get_context_window_size.return_value = 100  # force multiple chunks
+        mock_llm.acall = AsyncMock(
+            side_effect=[
+                "<summary>Summary chunk 1</summary>",
+                "<summary>Summary chunk 2</summary>",
+                "<summary>Summary chunk 3</summary>",
+            ]
+        )
+
+        summarize_messages(
+            messages=messages,
+            llm=mock_llm,
+            callbacks=[],
+            i18n=_make_mock_i18n(),
+        )
+
+        # acall should have been awaited once per chunk
+        assert mock_llm.acall.await_count == 3
+        # sync call should NOT have been used for chunk summarization
+        mock_llm.call.assert_not_called()
+
+    def test_single_chunk_uses_sync_call(self) -> None:
+        """When there is only one chunk, summarize_messages should use
+        the sync llm.call path (no async overhead)."""
+        messages: list[dict[str, Any]] = [
+            {"role": "user", "content": "Short message"},
+            {"role": "assistant", "content": "Short reply"},
+        ]
+
+        mock_llm = MagicMock()
+        mock_llm.get_context_window_size.return_value = 100_000
+        mock_llm.call.return_value = "<summary>Short summary</summary>"
+
+        summarize_messages(
+            messages=messages,
+            llm=mock_llm,
+            callbacks=[],
+            i18n=_make_mock_i18n(),
+        )
+
+        mock_llm.call.assert_called_once()
+
+    def test_parallel_results_preserve_order(self) -> None:
+        """Summaries must appear in the same order as the original chunks,
+        regardless of which async call finishes first."""
+        messages = self._make_messages_for_n_chunks(3)
+
+        mock_llm = MagicMock()
+        mock_llm.get_context_window_size.return_value = 100
+
+        # Simulate varying latencies — chunk 2 finishes before chunk 0
+        async def _delayed_acall(msgs: Any, **kwargs: Any) -> str:
+            user_content = msgs[1]["content"]
+            if "msg-0" in user_content:
+                await asyncio.sleep(0.05)
+                return "<summary>Summary-A</summary>"
+            elif "msg-1" in user_content:
+                return "<summary>Summary-B</summary>"  # fastest
+            else:
+                await asyncio.sleep(0.02)
+                return "<summary>Summary-C</summary>"
+
+        mock_llm.acall = _delayed_acall
+
+        summarize_messages(
+            messages=messages,
+            llm=mock_llm,
+            callbacks=[],
+            i18n=_make_mock_i18n(),
+        )
+
+        # The final summary message should have A, B, C in order
+        summary_content = messages[-1]["content"]
+        pos_a = summary_content.index("Summary-A")
+        pos_b = summary_content.index("Summary-B")
+        pos_c = summary_content.index("Summary-C")
+        assert pos_a < pos_b < pos_c
+
+    def test_asummarize_chunks_returns_ordered_results(self) -> None:
+        """Direct test of the async helper _asummarize_chunks."""
+        chunk_a: list[dict[str, Any]] = [{"role": "user", "content": "Chunk A"}]
+        chunk_b: list[dict[str, Any]] = [{"role": "user", "content": "Chunk B"}]
+
+        mock_llm = MagicMock()
+        mock_llm.acall = AsyncMock(
+            side_effect=[
+                "<summary>Result A</summary>",
+                "<summary>Result B</summary>",
+            ]
+        )
+
+        results = asyncio.run(
+            _asummarize_chunks(
+                chunks=[chunk_a, chunk_b],
+                llm=mock_llm,
+                callbacks=[],
+                i18n=_make_mock_i18n(),
+            )
+        )
+
+        assert len(results) == 2
+        assert results[0]["content"] == "Result A"
+        assert results[1]["content"] == "Result B"
+
+    @patch("crewai.utilities.agent_utils.is_inside_event_loop", return_value=True)
+    def test_works_inside_existing_event_loop(self, _mock_loop: Any) -> None:
+        """When called from inside a running event loop (e.g. a Flow),
+        the ThreadPoolExecutor fallback should still work."""
+        messages = self._make_messages_for_n_chunks(2)
+
+        mock_llm = MagicMock()
+        mock_llm.get_context_window_size.return_value = 100
+        mock_llm.acall = AsyncMock(
+            side_effect=[
+                "<summary>Flow summary 1</summary>",
+                "<summary>Flow summary 2</summary>",
+            ]
+        )
+
+        summarize_messages(
+            messages=messages,
+            llm=mock_llm,
+            callbacks=[],
+            i18n=_make_mock_i18n(),
+        )
+
+        assert mock_llm.acall.await_count == 2
+        # Verify the merged summary made it into messages
+        assert "Flow summary 1" in messages[-1]["content"]
+        assert "Flow summary 2" in messages[-1]["content"]
+
+
+def _build_long_conversation() -> list[dict[str, Any]]:
+    """Build a multi-turn conversation that produces multiple chunks at max_tokens=200.
+
+    Each non-system message is ~100-140 estimated tokens (400-560 chars),
+    so a max_tokens of 200 yields roughly 3 chunks from 6 messages.
+    """
+    return [
+        {
+            "role": "system",
+            "content": "You are a helpful research assistant.",
+        },
+        {
+            "role": "user",
+            "content": (
+                "Tell me about the history of the Python programming language. "
+                "Who created it, when was it first released, and what were the "
+                "main design goals? Please provide a detailed overview covering "
+                "the major milestones from its inception through Python 3."
+            ),
+        },
+        {
+            "role": "assistant",
+            "content": (
+                "Python was created by Guido van Rossum and first released in 1991. "
+                "The main design goals were code readability and simplicity. Key milestones: "
+                "Python 1.0 (1994) introduced functional programming tools like lambda and map. "
+                "Python 2.0 (2000) added list comprehensions and garbage collection. "
+                "Python 3.0 (2008) was a major backward-incompatible release that fixed "
+                "fundamental design flaws. Python 2 reached end-of-life in January 2020."
+            ),
+        },
+        {
+            "role": "user",
+            "content": (
+                "What about the async/await features? When were they introduced "
+                "and how do they compare to similar features in JavaScript and C#? "
+                "Also explain the Global Interpreter Lock and its implications."
+            ),
+        },
+        {
+            "role": "assistant",
+            "content": (
+                "Async/await was introduced in Python 3.5 (PEP 492, 2015). "
+                "Unlike JavaScript which is single-threaded by design, Python's asyncio "
+                "is an opt-in framework. C# introduced async/await in 2012 (C# 5.0) and "
+                "was a major inspiration for Python's implementation. "
+                "The GIL (Global Interpreter Lock) is a mutex that protects access to "
+                "Python objects, preventing multiple threads from executing Python bytecodes "
+                "simultaneously. This means CPU-bound multithreaded programs don't benefit "
+                "from multiple cores. PEP 703 proposes making the GIL optional in CPython."
+            ),
+        },
+        {
+            "role": "user",
+            "content": (
+                "Explain the Python package ecosystem. How does pip work, what is PyPI, "
+                "and what are virtual environments? Compare pip with conda and uv."
+            ),
+        },
+        {
+            "role": "assistant",
+            "content": (
+                "PyPI (Python Package Index) is the official repository hosting 400k+ packages. "
+                "pip is the standard package installer that downloads from PyPI. "
+                "Virtual environments (venv) create isolated Python installations to avoid "
+                "dependency conflicts between projects. conda is a cross-language package manager "
+                "popular in data science that can manage non-Python dependencies. "
+                "uv is a new Rust-based tool that is 10-100x faster than pip and aims to replace "
+                "pip, pip-tools, and virtualenv with a single unified tool."
+            ),
+        },
+    ]
+
+
+class TestParallelSummarizationVCR:
+    """VCR-backed integration tests for parallel summarization.
+
+    These tests use a real LLM but patch get_context_window_size to force
+    multiple chunks, exercising the asyncio.gather + acall parallel path.
+
+    To record cassettes:
+        PYTEST_VCR_RECORD_MODE=all uv run pytest lib/crewai/tests/utilities/test_agent_utils.py::TestParallelSummarizationVCR -v
+    """
+
+    @pytest.mark.vcr()
+    def test_parallel_summarize_openai(self) -> None:
+        """Test that parallel summarization with gpt-4o-mini produces a valid summary."""
+        from crewai.llm import LLM
+        from crewai.utilities.i18n import I18N
+
+        llm = LLM(model="gpt-4o-mini", temperature=0)
+        i18n = I18N()
+        messages = _build_long_conversation()
+
+        original_system = messages[0]["content"]
+
+        # Patch get_context_window_size to return 200 — forces multiple chunks
+        with patch.object(type(llm), "get_context_window_size", return_value=200):
+            # Verify we actually get multiple chunks with this window size
+            non_system = [m for m in messages if m.get("role") != "system"]
+            chunks = _split_messages_into_chunks(non_system, max_tokens=200)
+            assert len(chunks) > 1, f"Expected multiple chunks, got {len(chunks)}"
+
+            summarize_messages(
+                messages=messages,
+                llm=llm,
+                callbacks=[],
+                i18n=i18n,
+            )
+
+        # System message preserved
+        assert messages[0]["role"] == "system"
+        assert messages[0]["content"] == original_system
+
+        # Summary produced as a user message
+        summary_msg = messages[-1]
+        assert summary_msg["role"] == "user"
+        assert len(summary_msg["content"]) > 0
+
+    @pytest.mark.vcr()
+    def test_parallel_summarize_preserves_files(self) -> None:
+        """Test that file references survive parallel summarization."""
+        from crewai.llm import LLM
+        from crewai.utilities.i18n import I18N
+
+        llm = LLM(model="gpt-4o-mini", temperature=0)
+        i18n = I18N()
+        messages = _build_long_conversation()
+
+        mock_file = MagicMock()
+        messages[1]["files"] = {"report.pdf": mock_file}
+
+        with patch.object(type(llm), "get_context_window_size", return_value=200):
+            summarize_messages(
+                messages=messages,
+                llm=llm,
+                callbacks=[],
+                i18n=i18n,
+            )
+
+        summary_msg = messages[-1]
+        assert summary_msg["role"] == "user"
+        assert "files" in summary_msg
+        assert "report.pdf" in summary_msg["files"]