diff --git a/Library/Homebrew/utils/pypi.rb b/Library/Homebrew/utils/pypi.rb
index 17db37add5..d0d3a9e4a2 100644
--- a/Library/Homebrew/utils/pypi.rb
+++ b/Library/Homebrew/utils/pypi.rb
@@ -217,7 +217,7 @@ module PyPI
     ohai "Retrieving PyPI dependencies for \"#{input_packages.join(" ")}\"..." if !print_only && !silent
     command =
       [Formula["python"].bin/"python3", "-m", "pip", "install", "-q", "--dry-run", "--ignore-installed", "--report", "/dev/stdout", *input_packages.map(&:to_s)]
-    pipgrip_output = Utils.popen_read(*command)
+    pipgrip_output = Utils.popen_read(*command, env: { "PIP_REQUIRE_VIRTUALENV" => "false" })
     unless $CHILD_STATUS.success?
       odie <<~EOS
         Unable to determine dependencies for "#{input_packages.join(" ")}" because of a failure when running