diff --git a/pkgs/development/python-modules/flask-bcrypt/default.nix b/pkgs/development/python-modules/flask-bcrypt/default.nix
index a1f4cacc0cf6..83771359fcb6 100644
--- a/pkgs/development/python-modules/flask-bcrypt/default.nix
+++ b/pkgs/development/python-modules/flask-bcrypt/default.nix
@@ -19,6 +19,13 @@ buildPythonPackage rec {
     hash = "sha256-WlIholi/nzq6Ikc0LS6FhG0Q5Kz0kvvAlA2YJ7EksZ4=";
   };
 
+  postPatch = ''
+    # Backport fix for test_long_password from upstream PR: https://github.com/maxcountryman/flask-bcrypt/pull/96
+    substituteInPlace test_bcrypt.py \
+      --replace-fail "self.assertTrue(self.bcrypt.check_password_hash(pw_hash, 'A' * 80))" \
+                     "self.assertTrue(self.bcrypt.check_password_hash(pw_hash, 'A' * 72))"
+  '';
+
   propagatedBuildInputs = [
     flask
     bcrypt