diff --git a/src/poetry/version/version_selector.py b/src/poetry/version/version_selector.py
index d40fcc7953a..342b7649ca3 100644
--- a/src/poetry/version/version_selector.py
+++ b/src/poetry/version/version_selector.py
@@ -32,7 +32,7 @@ def find_best_candidate(
             package_name,
             {
                 "version": target_package_version or "*",
-                "allow_prereleases": allow_prereleases,
+                "allow-prereleases": allow_prereleases,
                 "source": source,
             },
         )