diff --git a/src/V3EmitMk.h b/src/V3EmitMk.h
index a23748fb0..0ddfdba66 100644
--- a/src/V3EmitMk.h
+++ b/src/V3EmitMk.h
@@ -26,6 +26,9 @@ class V3HierBlockPlan;
 
 class V3EmitMk final {
 public:
+    // Number of source files after which to use parallel compiles
+    static const size_t PARALLEL_FILE_CNT_THRESHOLD = 128;
+
     static void emitmk();
     static void emitHierVerilation(const V3HierBlockPlan* planp);
 };
diff --git a/src/Verilator.cpp b/src/Verilator.cpp
index a833335ea..294320613 100644
--- a/src/Verilator.cpp
+++ b/src/Verilator.cpp
@@ -565,6 +565,13 @@ static void process() {
     reportStatsIfEnabled();
 
     if (!v3Global.opt.lintOnly() && !v3Global.opt.xmlOnly() && !v3Global.opt.dpiHdrOnly()) {
+        size_t src_f_cnt = 0;
+        for (AstNode* nodep = v3Global.rootp()->filesp(); nodep; nodep = nodep->nextp()) {
+            if (const AstCFile* cfilep = VN_CAST(nodep, CFile))
+                src_f_cnt += cfilep->source() ? 1 : 0;
+        }
+        if (src_f_cnt >= V3EmitMk::PARALLEL_FILE_CNT_THRESHOLD) v3Global.useParallelBuild(true);
+
         // Makefile must be after all other emitters
         if (v3Global.opt.main()) V3EmitCMain::emit();
         if (v3Global.opt.cmake()) V3EmitCMake::emit();