diff --git a/Makefile.proof b/Makefile.proof
index a08e91c..0332323 100644
--- a/Makefile.proof
+++ b/Makefile.proof
@@ -77,7 +77,7 @@
 $(obj)/gnatprove/gnatprove.out: $$($(name)-extra-specs) $$($(name)-extra-gens)
 $(obj)/gnatprove/gnatprove.out: $(gpr) $(obj)/proofmode
 	$(call filter-output, \
-	  gnatprove -P$< $(SPARKFLAGS) -Xobj=$(abspath $(obj)), \
+	  $(MAKE) -j$(jobs) && gnatprove -P$< $(SPARKFLAGS) -Xobj=$(abspath $(obj)), \
 	  sed $(foreach file,$^,-e 's|$(notdir $(file)):[0-9]\+:[0-9]\+:|$(dir $(file))&|'))
 proof:
 	if [ "$(PROOF_MODE)" != "$$(cat $(obj)/proofmode 2>/dev/null)" ]; then \