diff --git a/src/scanpy/tools/_umap.py b/src/scanpy/tools/_umap.py
index 4f225da2a1..2d4dc9c2be 100644
--- a/src/scanpy/tools/_umap.py
+++ b/src/scanpy/tools/_umap.py
@@ -56,6 +56,7 @@ def umap(
     key_added: str | None = None,
     neighbors_key: str = "neighbors",
     copy: bool = False,
+    parallel: bool = False,
 ) -> AnnData | None:
     """\
     Embed the neighborhood graph using UMAP :cite:p:`McInnes2018`.
@@ -146,7 +147,8 @@ def umap(
         :attr:`~anndata.AnnData.obsp`\\ ``[.uns[neighbors_key]['connectivities_key']]`` for connectivities.
     copy
         Return a copy instead of writing to adata.
-
+    parallel
+        Whether to run the computation using numba parallel. Running in parallel is non-deterministic.
     Returns
     -------
     Returns `None` if `copy=False`, else returns an `AnnData` object. Sets the following fields:
@@ -214,6 +216,12 @@ def umap(
         # for the init condition in the UMAP embedding
         default_epochs = 500 if neighbors["connectivities"].shape[0] <= 10000 else 200
         n_epochs = default_epochs if maxiter is None else maxiter
+        if parallel and random_state is not None:
+            warnings.warn(
+                "Parallel execution was expected to be disabled when both `parallel=True` and `random_state` are set, "
+                "to ensure reproducibility. However, parallel execution still seems to occur, which may lead to "
+                "non-deterministic results."
+            )
         X_umap, _ = simplicial_set_embedding(
             data=X,
             graph=neighbors["connectivities"].tocoo(),
@@ -232,6 +240,7 @@ def umap(
             densmap_kwds={},
             output_dens=False,
             verbose=settings.verbosity > 3,
+            parallel=parallel,
         )
     elif method == "rapids":
         msg = (
diff --git a/tests/test_embedding.py b/tests/test_embedding.py
index 692157a084..c4377535c2 100644
--- a/tests/test_embedding.py
+++ b/tests/test_embedding.py
@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+import warnings
+
 import numpy as np
 import pytest
 from numpy.testing import assert_array_almost_equal, assert_array_equal, assert_raises
@@ -88,3 +90,28 @@ def test_diffmap():
     sc.tl.diffmap(pbmc, random_state=1234)
     d3 = pbmc.obsm["X_diffmap"].copy()
     assert_raises(AssertionError, assert_array_equal, d1, d3)
+
+
+@pytest.mark.parametrize(
+    ("random_state", "expect_warning"),
+    [
+        pytest.param(42, True, id="random_state_int"),
+        pytest.param(np.random.RandomState(42), True, id="random_state_RandomState"),
+        pytest.param(None, True, id="random_state_None"),
+    ],
+)
+def test_umap_parallel_randomstate(random_state, expect_warning):
+    pbmc = pbmc68k_reduced()[:100, :].copy()
+
+    if expect_warning:
+        with pytest.warns(
+            UserWarning, match="Parallel execution was expected to be disabled"
+        ):
+            sc.tl.umap(pbmc, parallel=True, random_state=random_state)
+    else:
+        # This is case is currently not in use because of lmcinnes/umap#1155
+        with warnings.catch_warnings(record=True) as record:
+            warnings.simplefilter("always")
+            sc.tl.umap(pbmc, parallel=True, random_state=random_state)
+
+        assert len(record) == 0