diff --git a/mlir/test/lib/Dialect/Test/TestOps.td b/mlir/test/lib/Dialect/Test/TestOps.td
--- a/mlir/test/lib/Dialect/Test/TestOps.td
+++ b/mlir/test/lib/Dialect/Test/TestOps.td
@@ -2174,6 +2174,11 @@
   let assemblyFormat = "($attr^)? attr-dict";
 }
 
+def FormatOptionalDefaultAttr : TEST_Op<"format_optional_default_attr"> {
+  let arguments = (ins DefaultValuedAttr<StrAttr, "\"default\"">:$attr);
+  let assemblyFormat = "($attr^)? attr-dict";
+}
+
 def FormatOptionalWithElse : TEST_Op<"format_optional_else"> {
   let arguments = (ins UnitAttr:$isFirstBranchPresent);
   let assemblyFormat = "(`then` $isFirstBranchPresent^):(`else`)? attr-dict";
diff --git a/mlir/test/mlir-tblgen/op-format-invalid.td b/mlir/test/mlir-tblgen/op-format-invalid.td
--- a/mlir/test/mlir-tblgen/op-format-invalid.td
+++ b/mlir/test/mlir-tblgen/op-format-invalid.td
@@ -369,7 +369,7 @@
 def OptionalInvalidF : TestFormat_Op<[{
   ($attr^ $attr2^)? attr-dict
 }]>, Arguments<(ins OptionalAttr<I64Attr>:$attr, OptionalAttr<I64Attr>:$attr2)>;
-// CHECK: error: only optional attributes can be used to anchor an optional group
+// CHECK: error: only optional or default-valued attributes can be used to anchor an optional group
 def OptionalInvalidG : TestFormat_Op<[{
   ($attr^)? attr-dict
 }]>, Arguments<(ins I64Attr:$attr)>;
diff --git a/mlir/test/mlir-tblgen/op-format.mlir b/mlir/test/mlir-tblgen/op-format.mlir
--- a/mlir/test/mlir-tblgen/op-format.mlir
+++ b/mlir/test/mlir-tblgen/op-format.mlir
@@ -197,6 +197,13 @@
 // CHECK-NOT: "case5"
 test.format_optional_enum_attr
 
+// CHECK: test.format_optional_default_attr "foo"
+test.format_optional_default_attr "foo"
+
+// CHECK: test.format_optional_default_attr
+// CHECK-NOT: default
+test.format_optional_default_attr "default"
+
 //===----------------------------------------------------------------------===//
 // Format optional operands and results
 //===----------------------------------------------------------------------===//
diff --git a/mlir/test/mlir-tblgen/op-format.td b/mlir/test/mlir-tblgen/op-format.td
--- a/mlir/test/mlir-tblgen/op-format.td
+++ b/mlir/test/mlir-tblgen/op-format.td
@@ -71,3 +71,13 @@
 def OptionalGroupB : TestFormat_Op<[{
   (`foo`) : (`bar` $a^)? attr-dict
 }]>, Arguments<(ins UnitAttr:$a)>;
+
+// Optional group anchored on a default-valued attribute:
+// CHECK-LABEL: OptionalGroupC::parse
+//       CHECK: if ((*this)->getAttr("a") != ::mlir::OpBuilder(getContext()).getStringAttr("default")) {
+//  CHECK-NEXT:   odsPrinter << ' ';
+//  CHECK-NEXT:   odsPrinter.printAttributeWithoutType(getAAttr());
+//  CHECK-NEXT: }
+def OptionalGroupC : TestFormat_Op<[{
+  ($a^)? attr-dict
+}]>, Arguments<(ins DefaultValuedAttr<StrAttr, "\"default\"">:$a)>;
diff --git a/mlir/tools/mlir-tblgen/OpFormatGen.cpp b/mlir/tools/mlir-tblgen/OpFormatGen.cpp
--- a/mlir/tools/mlir-tblgen/OpFormatGen.cpp
+++ b/mlir/tools/mlir-tblgen/OpFormatGen.cpp
@@ -1142,8 +1142,7 @@
       // an optional group after the guard are parsed as required.
       for (FormatElement *childElement : elements)
         if (childElement != elidedAnchorElement)
-          genElementParser(childElement, body, attrTypeCtx,
-                           GenContext::Optional);
+          genElementParser(childElement, body, attrTypeCtx);
     };
 
     ArrayRef<FormatElement *> thenElements =
@@ -1153,7 +1152,7 @@
     // parsing of the rest of the elements.
     FormatElement *firstElement = thenElements.front();
     if (auto *attrVar = dyn_cast<AttributeVariable>(firstElement)) {
-      genElementParser(attrVar, body, attrTypeCtx);
+      genElementParser(attrVar, body, attrTypeCtx, GenContext::Optional);
       body << "  if (" << attrVar->getVar()->name << "Attr) {\n";
     } else if (auto *literal = dyn_cast<LiteralElement>(firstElement)) {
       body << "  if (::mlir::succeeded(parser.parseOptional";
@@ -1259,7 +1258,7 @@
     } else {
       attrTypeStr = "::mlir::Type{}";
     }
-    if (genCtx == GenContext::Normal && var->attr.isOptional()) {
+    if (genCtx == GenContext::Optional) {
       body << formatv(optionalAttrParserCode, var->name, attrTypeStr);
     } else {
       if (attr->shouldBeQualified() ||
@@ -1872,8 +1871,22 @@
       .Case<FunctionalTypeDirective>([&](FunctionalTypeDirective *element) {
         genOptionalGroupPrinterAnchor(element->getInputs(), op, body);
       })
-      .Case<AttributeVariable>([&](AttributeVariable *attr) {
-        body << "(*this)->getAttr(\"" << attr->getVar()->name << "\")";
+      .Case<AttributeVariable>([&](AttributeVariable *element) {
+        Attribute attr = element->getVar()->attr;
+        body << "(*this)->getAttr(\"" << element->getVar()->name << "\")";
+        if (attr.isOptional())
+          return; // done
+        if (attr.hasDefaultValue()) {
+          // Consider a default-valued attribute as present if it's not the
+          // default value.
+          FmtContext fctx;
+          fctx.withBuilder("::mlir::OpBuilder(getContext())");
+          body << " != "
+               << tgfmt(attr.getConstBuilderTemplate(), &fctx,
+                        attr.getDefaultValue());
+          return;
+        }
+        llvm_unreachable("attribute must be optional or default-valued");
       });
 }
 
@@ -3185,9 +3198,10 @@
       // All attributes can be within the optional group, but only optional
       // attributes can be the anchor.
       .Case([&](AttributeVariable *attrEle) {
-        if (isAnchor && !attrEle->getVar()->attr.isOptional())
-          return emitError(loc, "only optional attributes can be used to "
-                                "anchor an optional group");
+        Attribute attr = attrEle->getVar()->attr;
+        if (isAnchor && !(attr.isOptional() || attr.hasDefaultValue()))
+          return emitError(loc, "only optional or default-valued attributes "
+                                "can be used to anchor an optional group");
         return success();
       })
       // Only optional-like(i.e. variadic) operands can be within an optional