diff --git a/mlir/docs/OpDefinitions.md b/mlir/docs/OpDefinitions.md
--- a/mlir/docs/OpDefinitions.md
+++ b/mlir/docs/OpDefinitions.md
@@ -746,9 +746,9 @@
 identifier used as a suffix to these two calls, i.e., `custom<MyDirective>(...)`
 would result in calls to `parseMyDirective` and `printMyDirective` wihtin the
 parser and printer respectively. `Params` may be any combination of variables
-(i.e. Attribute, Operand, Successor, etc.) and type directives. The type
-directives must refer to a variable, but that variable need not also be a
-parameter to the custom directive.
+(i.e. Attribute, Operand, Successor, etc.), type directives, and `attr-dict`.
+The type directives must refer to a variable, but that variable need not also
+be a parameter to the custom directive.
 
 The arguments to the `parse<UserDirective>` method is firstly a reference to the
 `OpAsmParser`(`OpAsmParser &`), and secondly a set of output parameters
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
@@ -845,7 +845,8 @@
   body << ", ";
   if (auto *attr = dyn_cast<AttributeVariable>(&param)) {
     body << attr->getVar()->name << "Attr";
-
+  } else if (auto *attrDict = dyn_cast<AttrDictDirective>(&param)) {
+    body << "result.attributes";
   } else if (auto *operand = dyn_cast<OperandVariable>(&param)) {
     StringRef name = operand->getVar()->name;
     ArgumentLengthKind lengthKind = getArgumentLengthKind(operand->getVar());
@@ -1478,7 +1479,8 @@
     body << ", ";
     if (auto *attr = dyn_cast<AttributeVariable>(&param)) {
       body << attr->getVar()->name << "Attr()";
-
+    } else if (auto *attrDict = dyn_cast<AttrDictDirective>(&param)) {
+      body << "this";
     } else if (auto *operand = dyn_cast<OperandVariable>(&param)) {
       body << operand->getVar()->name << "()";
 
@@ -2735,8 +2737,9 @@
     return ::mlir::failure();
 
   // Verify that the element can be placed within a custom directive.
-  if (!isa<TypeRefDirective, TypeDirective, AttributeVariable, OperandVariable,
-           RegionVariable, SuccessorVariable>(parameters.back().get())) {
+  if (!isa<TypeRefDirective, TypeDirective, AttrDictDirective,
+           AttributeVariable, OperandVariable, RegionVariable,
+           SuccessorVariable>(parameters.back().get())) {
     return emitError(childLoc, "only variables and types may be used as "
                                "parameters to a custom directive");
   }