diff --git a/gnu/packages/python-web.scm b/gnu/packages/python-web.scm
index 1eb14e8b28..23ea2edb20 100644
--- a/gnu/packages/python-web.scm
+++ b/gnu/packages/python-web.scm
@@ -2841,8 +2841,6 @@ (define-public python-flask
        (modify-phases %standard-phases
          (replace 'check
            (lambda _
-             (setenv "PYTHONPATH" (string-append "./build/lib:"
-                                                 (getenv "PYTHONPATH")))
              (invoke "pytest" "-vv" "tests"))))))
     (native-inputs
      `(("python-pytest" ,python-pytest)))