diff --git a/lib/Dialect/FIRRTL/Transforms/AdvancedLayerSink.cpp b/lib/Dialect/FIRRTL/Transforms/AdvancedLayerSink.cpp
index a567e8cfac99..af3f16de78e1 100644
--- a/lib/Dialect/FIRRTL/Transforms/AdvancedLayerSink.cpp
+++ b/lib/Dialect/FIRRTL/Transforms/AdvancedLayerSink.cpp
@@ -111,9 +111,18 @@ class EffectInfo {
     });
   }
 
+  /// Record whether the module-like op contains any effectful op.
   void update(FModuleLike moduleOp) {
-    if (!AnnotationSet(moduleOp).empty())
-      return markEffectful(moduleOp);
+    // If the module op has any annotations, then we pretend the module contains
+    // some kind of important effect, so that we cannot sink its instances.
+    if (auto annos = getAnnotationsIfPresent(moduleOp))
+      if (!annos.empty())
+        return markEffectful(moduleOp);
+
+    for (auto annos : moduleOp.getPortAnnotations())
+      if (!cast<ArrayAttr>(annos).empty())
+        return markEffectful(moduleOp);
+
     auto *op = moduleOp.getOperation();
     // Regular modules may be pure.
     if (auto m = dyn_cast<FModuleOp>(op))
diff --git a/test/Dialect/FIRRTL/advanced-layer-sink.mlir b/test/Dialect/FIRRTL/advanced-layer-sink.mlir
index 190922151546..73a1927b4e1b 100644
--- a/test/Dialect/FIRRTL/advanced-layer-sink.mlir
+++ b/test/Dialect/FIRRTL/advanced-layer-sink.mlir
@@ -715,3 +715,26 @@ firrtl.circuit "Sub" {
     }
   }
 }
+
+// Test that a port annotation on a module prevents us from sinking instances of
+// that module into layerblocks.
+firrtl.circuit "DoNotSinkInstanceOfModuleWithPortAnno" {
+  firrtl.layer @A bind {}
+  firrtl.module @ModuleWithPortAnno(out %out : !firrtl.uint<1>)
+    attributes {
+      portAnnotations = [
+        [{class = "circt.FullResetAnnotation", resetType = "async"}]
+      ]
+    }
+  {}
+
+  // CHECK: firrtl.module @DoNotSinkInstanceOfModuleWithPortAnno
+  firrtl.module @DoNotSinkInstanceOfModuleWithPortAnno() {
+    // CHECK-NEXT: firrtl.instance foo @ModuleWithPortAnn
+    %foo_out = firrtl.instance foo @ModuleWithPortAnno(out out : !firrtl.uint<1>)
+    // CHECK-NEXT: firrtl.layerblock 
+    firrtl.layerblock @A {
+      "unknown"(%foo_out) : (!firrtl.uint<1>) -> ()
+    }
+  }
+}