diff --git a/changes/4305.bugfix.md b/changes/4305.bugfix.md
new file mode 100644
index 0000000000..13221d8e3b
--- /dev/null
+++ b/changes/4305.bugfix.md
@@ -0,0 +1 @@
+Fixed an infinite loop when creating a 0-dimensional array with `shards="auto"` while the `array.target_shard_size_bytes` config option is set. Such arrays now resolve to `shards=()`, matching the behavior when no shard size target is configured.
diff --git a/src/zarr/core/chunk_grids.py b/src/zarr/core/chunk_grids.py
index 584829bc6c..5e19364cae 100644
--- a/src/zarr/core/chunk_grids.py
+++ b/src/zarr/core/chunk_grids.py
@@ -865,6 +865,8 @@ def _guess_num_chunks_per_axis_shard(
     if max_bytes < bytes_per_chunk:
         return 1
     num_axes = len(chunk_shape)
+    if num_axes == 0:
+        return 1
     chunks_per_shard = 1
     # First check for byte size, second check to make sure we don't go bigger than the array shape
     while (bytes_per_chunk * ((chunks_per_shard + 1) ** num_axes)) <= max_bytes and all(
diff --git a/tests/test_chunk_grids.py b/tests/test_chunk_grids.py
index 4640c43d1c..4c3c437eb2 100644
--- a/tests/test_chunk_grids.py
+++ b/tests/test_chunk_grids.py
@@ -3,14 +3,17 @@
 import numpy as np
 import pytest
 
+import zarr
 from tests.conftest import Expect, ExpectFail
 from zarr.core.chunk_grids import (
     ChunkLayout,
+    _guess_num_chunks_per_axis_shard,
     _guess_regular_chunks,
     normalize_chunks_1d,
     normalize_chunks_nd,
     resolve_outer_and_inner_chunks,
 )
+from zarr.errors import ZarrUserWarning
 
 
 def _assert_chunks_equal(
@@ -277,3 +280,26 @@ def test_normalize_chunks_1d_returns_int64_array(
     assert result.dtype == np.int64
     assert result.ndim == 1
     assert result.tolist() == case.output
+
+
+def test_guess_num_chunks_per_axis_shard_0d() -> None:
+    """Regression test for https://github.com/zarr-developers/zarr-python/issues/4304."""
+    assert (
+        _guess_num_chunks_per_axis_shard(
+            chunk_shape=(), item_size=8, max_bytes=128 * 1024 * 1024, array_shape=()
+        )
+        == 1
+    )
+
+
+def test_create_0d_array_auto_shards_with_target_shard_size() -> None:
+    """A 0-dimensional array with shards="auto" and a shard size budget must not hang.
+
+    Regression test for https://github.com/zarr-developers/zarr-python/issues/4304.
+    """
+    with (
+        zarr.config.set({"array.target_shard_size_bytes": 128 * 1024 * 1024}),
+        pytest.warns(ZarrUserWarning, match="Automatic shard shape inference is experimental"),
+    ):
+        arr = zarr.create_array(store={}, shape=(), dtype="int64", shards="auto")
+    assert arr.shards == ()