diff --git a/src/nix/installables.cc b/src/nix/installables.cc
index bc8fbeb8f..38f37adb1 100644
--- a/src/nix/installables.cc
+++ b/src/nix/installables.cc
@@ -409,7 +409,7 @@ std::vector<std::shared_ptr<Installable>> SourceExprCommand::parseInstallables(
                 bool static warned;
                 warnOnce(warned, "the syntax 'nixpkgs.<attr>' is deprecated; use 'nixpkgs:<attr>' instead");
                 result.push_back(std::make_shared<InstallableFlake>(*this, FlakeRef("nixpkgs"),
-                        Strings{"legacyPackages." + std::string(s, 8)}));
+                        Strings{"legacyPackages." + settings.thisSystem.get() + "." + std::string(s, 8)}));
             }
 
             else if ((hash = s.rfind('#')) != std::string::npos)