diff --git a/liberty/LibertyBuilder.cc b/liberty/LibertyBuilder.cc
index 4f57805b..2d4b4a70 100644
--- a/liberty/LibertyBuilder.cc
+++ b/liberty/LibertyBuilder.cc
@@ -692,10 +692,10 @@ LibertyBuilder::makeMinPulseWidthArcs(LibertyCell *cell,
     from_port = to_port;
   TimingArcSet *arc_set = makeTimingArcSet(cell, from_port, to_port, related_out,
                                            role, attrs);
-  for (auto to_rf : RiseFall::range()) {
-    TimingModel *model = attrs->model(to_rf);
+  for (const RiseFall *from_rf : RiseFall::range()) {
+    TimingModel *model = attrs->model(from_rf);
     if (model)
-      makeTimingArc(arc_set, to_rf->opposite(), to_rf, model);
+      makeTimingArc(arc_set, from_rf, from_rf->opposite(), model);
   }
   return arc_set;
 }
diff --git a/liberty/LibertyReader.cc b/liberty/LibertyReader.cc
index 3c223fa4..e9aa2c35 100644
--- a/liberty/LibertyReader.cc
+++ b/liberty/LibertyReader.cc
@@ -2027,8 +2027,8 @@ LibertyReader::makeMinPulseWidthArcs(LibertyPort *port,
         attrs = make_shared<TimingArcAttrs>();
         attrs->setTimingType(TimingType::min_pulse_width);
       }
-      // rise/fall_constraint model is on the trailing edge of the pulse.
-      const RiseFall *model_rf = hi_low->opposite();
+      // rise/fall_constraint model is on the leading edge of the pulse.
+      const RiseFall *model_rf = hi_low;
       TimingModel *check_model =
         makeScalarCheckModel(min_width, ScaleFactorType::min_pulse_width, model_rf);
       attrs->setModel(model_rf, check_model);
diff --git a/liberty/LibertyWriter.cc b/liberty/LibertyWriter.cc
index 4d7cb6c2..e3d31312 100644
--- a/liberty/LibertyWriter.cc
+++ b/liberty/LibertyWriter.cc
@@ -426,8 +426,13 @@ LibertyWriter::writeTimingArcSet(const TimingArcSet *arc_set)
 
   for (const RiseFall *rf : RiseFall::range()) {
     TimingArc *arc = arc_set->arcTo(rf);
-    if (arc)
-      writeTimingModels(arc, rf);
+    if (arc) {
+      // Min pulse width arcs are wrt to the leading edge of the pulse.
+      const RiseFall *model_rf = (arc_set->role() == TimingRole::width())
+        ? rf->opposite()
+        : rf;
+      writeTimingModels(arc, model_rf);
+    }
   }
 
   fprintf(stream_, "      }\n");