diff --git a/tests/unit/forklift/test_legacy.py b/tests/unit/forklift/test_legacy.py
index 463e0cb9cddd..41c542153eeb 100644
--- a/tests/unit/forklift/test_legacy.py
+++ b/tests/unit/forklift/test_legacy.py
@@ -2611,6 +2611,81 @@ def storage_service_store(path, file_path, *, meta):
         # Ensure that a Filename object has been created.
         db_request.db.query(Filename).filter(Filename.filename == filename).one()
 
+    @pytest.mark.parametrize(
+        "project_name, filename_prefix, version",
+        [
+            ("flufl.enum", "flufl_enum", "1.0.0"),
+            ("foo-.bar", "foo_bar", "1.0.0"),
+            ("leo", "leo", "6.7.9-9"),
+            ("leo_something", "leo-something", "6.7.9-9"),
+        ],
+    )
+    def test_upload_succeeds_pep625_normalized_filename(
+        self,
+        monkeypatch,
+        db_request,
+        pyramid_config,
+        metrics,
+        project_name,
+        filename_prefix,
+        version,
+    ):
+        user = UserFactory.create()
+        EmailFactory.create(user=user)
+        project = ProjectFactory.create(name=project_name)
+        RoleFactory.create(user=user, project=project)
+
+        filename = f"{filename_prefix}-{version}.tar.gz"
+        filebody = _get_whl_testdata(name=project_name, version=version)
+
+        @pretend.call_recorder
+        def storage_service_store(path, file_path, *, meta):
+            with open(file_path, "rb") as fp:
+                if file_path.endswith(".metadata"):
+                    assert fp.read() == b"Fake metadata"
+                else:
+                    assert fp.read() == filebody
+
+        storage_service = pretend.stub(store=storage_service_store)
+
+        db_request.find_service = pretend.call_recorder(
+            lambda svc, name=None, context=None: {
+                IFileStorage: storage_service,
+                IMetricsService: metrics,
+            }.get(svc)
+        )
+
+        monkeypatch.setattr(legacy, "_is_valid_dist_file", lambda *a, **kw: True)
+
+        pyramid_config.testing_securitypolicy(identity=user)
+        db_request.user = user
+        db_request.user_agent = "warehouse-tests/6.6.6"
+        db_request.POST = MultiDict(
+            {
+                "metadata_version": "1.2",
+                "name": project.name,
+                "version": version,
+                "filetype": "sdist",
+                "pyversion": "source",
+                "md5_digest": hashlib.md5(filebody).hexdigest(),
+                "content": pretend.stub(
+                    filename=filename,
+                    file=io.BytesIO(filebody),
+                    type="application/zip",
+                ),
+            }
+        )
+
+        resp = legacy.file_upload(db_request)
+
+        assert resp.status_code == 200
+
+        # Ensure that a File object has been created.
+        db_request.db.query(File).filter(File.filename == filename).one()
+
+        # Ensure that a Filename object has been created.
+        db_request.db.query(Filename).filter(Filename.filename == filename).one()
+
     def test_upload_succeeds_with_wheel_after_sdist(
         self, tmpdir, monkeypatch, pyramid_config, db_request, metrics
     ):
diff --git a/warehouse/forklift/legacy.py b/warehouse/forklift/legacy.py
index a9c07d59c7b4..75901f829410 100644
--- a/warehouse/forklift/legacy.py
+++ b/warehouse/forklift/legacy.py
@@ -804,9 +804,25 @@ def file_upload(request):
         # we can split on the first hyphen.
         filename.partition("-")[0]
         if filename.endswith(".whl")
-        # For source releases, we know that the version should not contain any
-        # hyphens, so we can split on the last hyphen to get the project name.
-        else filename.rpartition("-")[0]
+        # For source releases, the version might contain a hyphen as a
+        # post-release separator, so we get the prefix by removing the provided
+        # version.
+        # Per 625, the version should be normalized, but we aren't currently
+        # enforcing this, so we permit a filename with either the exact
+        # provided version if it contains a hyphen, or any version that doesn't
+        # contain a hyphen.
+        else (
+            # A hyphen is being used for a post-release separator, so partition
+            # the prefix twice
+            filename.rpartition("-")[0].rpartition("-")[0]
+            # Check if the provided version contains a hyphen and the same
+            # version is being used in the filename
+            if "-" in form.version.data
+            and filename.endswith(f"-{form.version.data}.tar.gz")
+            # The only hyphen should be between the prefix and the version, so
+            # we only need to partition the prefix once
+            else filename.rpartition("-")[0]
+        )
     )
 
     # Normalize the prefix in the filename. Eventually this should be unnecessary once