diff --git a/lib/cli/src/crewai_cli/run_crew.py b/lib/cli/src/crewai_cli/run_crew.py
index 549a8c035..03eeb2a92 100644
--- a/lib/cli/src/crewai_cli/run_crew.py
+++ b/lib/cli/src/crewai_cli/run_crew.py
@@ -258,8 +258,24 @@ def _run_json_crew(trained_agents_file: str | None = None) -> Any:
 
 def _has_lockfile(project_root: Path | None = None) -> bool:
     """Return True when the project already has a dependency lockfile."""
+    return _has_uv_lockfile(project_root) or _has_poetry_lockfile(project_root)
+
+
+def _has_uv_lockfile(project_root: Path | None = None) -> bool:
+    """Return True when the project has a uv lockfile."""
     root = project_root or Path.cwd()
-    return (root / "uv.lock").is_file() or (root / "poetry.lock").is_file()
+    return (root / "uv.lock").is_file()
+
+
+def _has_poetry_lockfile(project_root: Path | None = None) -> bool:
+    """Return True when the project has a Poetry lockfile."""
+    root = project_root or Path.cwd()
+    return (root / "poetry.lock").is_file()
+
+
+def _uses_poetry_lockfile(project_root: Path | None = None) -> bool:
+    """Return True when Poetry is the only available lock source."""
+    return _has_poetry_lockfile(project_root) and not _has_uv_lockfile(project_root)
 
 
 def _has_project_venv(project_root: Path | None = None) -> bool:
@@ -274,14 +290,17 @@ def _install_json_crew_dependencies_if_needed() -> None:
     if not (project_root / "pyproject.toml").is_file():
         return
 
-    has_lockfile = _has_lockfile(project_root)
+    has_uv_lockfile = _has_uv_lockfile(project_root)
+    has_lockfile = has_uv_lockfile or _has_poetry_lockfile(project_root)
     if has_lockfile and _has_project_venv(project_root):
         return
+    if _uses_poetry_lockfile(project_root):
+        return
 
     from crewai_cli.install_crew import install_crew
 
     try:
-        if has_lockfile:
+        if has_uv_lockfile:
             click.echo("Syncing dependencies from lockfile...")
             install_crew(["--frozen"], raise_on_error=True)
         else:
@@ -302,6 +321,13 @@ def _find_local_crewai_source_dir() -> Path | None:
     return None
 
 
+def _json_crew_run_command(project_root: Path | None = None) -> list[str]:
+    """Return the project-environment command for running JSON crews."""
+    if _uses_poetry_lockfile(project_root):
+        return ["poetry", "run", "python", "-c", _JSON_CREW_RUNNER_CODE]
+    return ["uv", "run", "--no-sync", "python", "-c", _JSON_CREW_RUNNER_CODE]
+
+
 def _run_json_crew_in_project_env(trained_agents_file: str | None = None) -> Any:
     """Run JSON crews from the project's uv-managed environment."""
     if not (Path.cwd() / "pyproject.toml").is_file():
@@ -309,7 +335,7 @@ def _run_json_crew_in_project_env(trained_agents_file: str | None = None) -> Any
 
     _install_json_crew_dependencies_if_needed()
 
-    command = ["uv", "run", "--no-sync", "python", "-c", _JSON_CREW_RUNNER_CODE]
+    command = _json_crew_run_command()
     env = build_env_with_all_tool_credentials()
     env[_CREWAI_CLI_RUNNER_PACKAGE_DIR_ENV] = str(Path(__file__).resolve().parent)
     if local_crewai_source_dir := _find_local_crewai_source_dir():
diff --git a/lib/cli/tests/test_run_crew.py b/lib/cli/tests/test_run_crew.py
index 49f2310a0..d6565c2cc 100644
--- a/lib/cli/tests/test_run_crew.py
+++ b/lib/cli/tests/test_run_crew.py
@@ -90,6 +90,60 @@ def test_json_run_uses_project_env_when_pyproject_exists(monkeypatch, tmp_path:
     ]
 
 
+def test_json_run_uses_poetry_run_for_poetry_lock_without_uv_lock(
+    monkeypatch, tmp_path: Path
+):
+    monkeypatch.chdir(tmp_path)
+    (tmp_path / "pyproject.toml").write_text("[project]\nname = 'demo'\n")
+    (tmp_path / "poetry.lock").write_text("# lock\n")
+    monkeypatch.setattr(
+        run_crew_module,
+        "_install_json_crew_dependencies_if_needed",
+        lambda: None,
+    )
+    monkeypatch.setattr(
+        run_crew_module,
+        "build_env_with_all_tool_credentials",
+        lambda: {},
+    )
+    subprocess_calls = []
+
+    def fake_subprocess_run(command, **kwargs):
+        subprocess_calls.append((command, kwargs))
+
+    monkeypatch.setattr(run_crew_module.subprocess, "run", fake_subprocess_run)
+
+    run_crew_module._run_json_crew_in_project_env()
+
+    expected_env = {
+        run_crew_module._CREWAI_CLI_RUNNER_PACKAGE_DIR_ENV: str(
+            Path(run_crew_module.__file__).resolve().parent
+        ),
+    }
+    if local_crewai_source_dir := run_crew_module._find_local_crewai_source_dir():
+        expected_env[run_crew_module._CREWAI_RUNNER_SOURCE_DIR_ENV] = str(
+            local_crewai_source_dir
+        )
+
+    assert subprocess_calls == [
+        (
+            [
+                "poetry",
+                "run",
+                "python",
+                "-c",
+                run_crew_module._JSON_CREW_RUNNER_CODE,
+            ],
+            {
+                "capture_output": False,
+                "text": True,
+                "check": True,
+                "env": expected_env,
+            },
+        )
+    ]
+
+
 def test_json_runner_code_loads_current_cli_package_over_project_env(tmp_path: Path):
     old_parent = tmp_path / "old"
     old_pkg = old_parent / "crewai_cli"
@@ -199,13 +253,12 @@ def test_json_run_installs_dependencies_when_pyproject_has_no_lockfile(
     assert calls == [([], True, None)]
 
 
-@pytest.mark.parametrize("lockfile", ["uv.lock", "poetry.lock"])
-def test_json_run_syncs_frozen_when_lockfile_exists_without_venv(
-    monkeypatch, tmp_path: Path, lockfile: str
+def test_json_run_syncs_frozen_when_uv_lock_exists_without_venv(
+    monkeypatch, tmp_path: Path
 ):
     monkeypatch.chdir(tmp_path)
     (tmp_path / "pyproject.toml").write_text("[project]\nname = 'demo'\n")
-    (tmp_path / lockfile).write_text("# lock\n")
+    (tmp_path / "uv.lock").write_text("# lock\n")
     calls = []
 
     def fake_install_crew(
@@ -220,6 +273,26 @@ def test_json_run_syncs_frozen_when_lockfile_exists_without_venv(
     assert calls == [(["--frozen"], True, None)]
 
 
+def test_json_run_skips_uv_sync_when_only_poetry_lock_exists_without_venv(
+    monkeypatch, tmp_path: Path
+):
+    monkeypatch.chdir(tmp_path)
+    (tmp_path / "pyproject.toml").write_text("[project]\nname = 'demo'\n")
+    (tmp_path / "poetry.lock").write_text("# lock\n")
+    calls = []
+
+    def fake_install_crew(
+        proxy_options, *, raise_on_error=False, install_project=None
+    ):
+        calls.append((proxy_options, raise_on_error, install_project))
+
+    monkeypatch.setattr("crewai_cli.install_crew.install_crew", fake_install_crew)
+
+    run_crew_module._install_json_crew_dependencies_if_needed()
+
+    assert calls == []
+
+
 @pytest.mark.parametrize("lockfile", ["uv.lock", "poetry.lock"])
 def test_json_run_skips_dependency_install_when_lockfile_and_venv_exist(
     monkeypatch, tmp_path: Path, lockfile: str