diff --git a/src/poetry/publishing/publisher.py b/src/poetry/publishing/publisher.py
index f752a0d5ee4..23bddc1eb35 100644
--- a/src/poetry/publishing/publisher.py
+++ b/src/poetry/publishing/publisher.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import logging
+import urllib.parse
 
 from typing import TYPE_CHECKING
 
@@ -18,6 +19,16 @@
 logger = logging.getLogger(__name__)
 
 
+def _normalize_legacy_repository_url(url: str) -> str:
+    parsed = urllib.parse.urlsplit(url)
+
+    if parsed.path.endswith("/legacy") and not parsed.path.endswith("/legacy/"):
+        parsed = parsed._replace(path=f"{parsed.path}/")
+        return urllib.parse.urlunsplit(parsed)
+
+    return url
+
+
 class Publisher:
     """
     Registers and publishes packages to remote repositories.
@@ -52,6 +63,7 @@ def publish(
             url = self._poetry.config.get(f"repositories.{repository_name}.url")
             if url is None:
                 raise RuntimeError(f"Repository {repository_name} is not defined")
+            url = _normalize_legacy_repository_url(url)
 
         if not (username and password):
             # Check if we have a token first
diff --git a/tests/publishing/test_publisher.py b/tests/publishing/test_publisher.py
index 53f30e75f78..8d4300a91be 100644
--- a/tests/publishing/test_publisher.py
+++ b/tests/publishing/test_publisher.py
@@ -82,6 +82,31 @@ def test_publish_can_publish_to_given_repository(
     assert f"Publishing {project_name} ({uploader_version}) to foo" in io.fetch_output()
 
 
+def test_publish_normalizes_legacy_repository_url_without_trailing_slash(
+    fixture_dir: FixtureDirGetter, mocker: MockerFixture, config: Config
+) -> None:
+    uploader_auth = mocker.patch("poetry.publishing.uploader.Uploader.auth")
+    uploader_upload = mocker.patch("poetry.publishing.uploader.Uploader.upload")
+
+    poetry = Factory().create_poetry(fixture_dir("sample_project"))
+    poetry._config = config
+    poetry.config.merge(
+        {
+            "repositories": {"testpypi": {"url": "https://test.pypi.org/legacy"}},
+            "http-basic": {"testpypi": {"username": "foo", "password": "bar"}},
+        }
+    )
+
+    publisher = Publisher(poetry, NullIO())
+    publisher.publish("testpypi", None, None)
+
+    assert uploader_auth.call_args == [("foo", "bar")]
+    assert uploader_upload.call_args == [
+        ("https://test.pypi.org/legacy/",),
+        {"cert": True, "client_cert": None, "dry_run": False, "skip_existing": False},
+    ]
+
+
 def test_publish_raises_error_for_undefined_repository(
     fixture_dir: FixtureDirGetter, config: Config
 ) -> None: