diff --git a/Makefile b/Makefile
index 3d8bf5436b476..735d342a79eb5 100644
--- a/Makefile
+++ b/Makefile
@@ -382,6 +382,11 @@ endif
 	cp -R -L $(JULIAHOME)/base/* $(DESTDIR)$(datarootdir)/julia/base
 	cp -R -L $(JULIAHOME)/test/* $(DESTDIR)$(datarootdir)/julia/test
 	cp -R -L $(build_datarootdir)/julia/* $(DESTDIR)$(datarootdir)/julia
+
+	# Set .jl sources as read-only to match package directories
+	find $(DESTDIR)$(datarootdir)/julia/base -type f -name \*.jl -exec chmod 0444 '{}' \;
+	find $(DESTDIR)$(datarootdir)/julia/test -type f -name \*.jl -exec chmod 0444 '{}' \;
+
 	# Copy documentation
 	cp -R -L $(BUILDROOT)/doc/_build/html $(DESTDIR)$(docdir)/
 	# Remove various files which should not be installed