diff --git a/mlir/include/mlir/IR/Dialect.h b/mlir/include/mlir/IR/Dialect.h
--- a/mlir/include/mlir/IR/Dialect.h
+++ b/mlir/include/mlir/IR/Dialect.h
@@ -239,7 +239,8 @@
   using MapTy =
       std::map<std::string, std::pair<TypeID, DialectAllocatorFunction>>;
   using InterfaceMapTy =
-      DenseMap<TypeID, SmallVector<InterfaceAllocatorFunction, 2>>;
+      DenseMap<TypeID,
+               SmallVector<std::pair<TypeID, InterfaceAllocatorFunction>, 2>>;
 
 public:
   explicit DialectRegistry() {}
@@ -292,17 +293,20 @@
   /// dialect provided as template parameter. The dialect must be present in
   /// the registry.
   template <typename DialectTy>
-  void addDialectInterface(InterfaceAllocatorFunction allocator) {
-    addDialectInterface(DialectTy::getDialectNamespace(), allocator);
+  void addDialectInterface(TypeID interfaceTypeID,
+                           InterfaceAllocatorFunction allocator) {
+    addDialectInterface(DialectTy::getDialectNamespace(), interfaceTypeID,
+                        allocator);
   }
 
   /// Add an interface to the dialect, both provided as template parameter. The
   /// dialect must be present in the registry.
   template <typename DialectTy, typename InterfaceTy>
   void addDialectInterface() {
-    addDialectInterface<DialectTy>([](Dialect *dialect) {
-      return std::make_unique<InterfaceTy>(dialect);
-    });
+    addDialectInterface<DialectTy>(
+        InterfaceTy::getInterfaceID(), [](Dialect *dialect) {
+          return std::make_unique<InterfaceTy>(dialect);
+        });
   }
 
   /// Register any interfaces required for the given dialect (based on its
@@ -312,7 +316,7 @@
 private:
   /// Add an interface constructed with the given allocation function to the
   /// dialect identified by its namespace.
-  void addDialectInterface(StringRef dialectName,
+  void addDialectInterface(StringRef dialectName, TypeID interfaceTypeID,
                            InterfaceAllocatorFunction allocator);
 
   MapTy registry;
diff --git a/mlir/lib/IR/Dialect.cpp b/mlir/lib/IR/Dialect.cpp
--- a/mlir/lib/IR/Dialect.cpp
+++ b/mlir/lib/IR/Dialect.cpp
@@ -14,9 +14,12 @@
 #include "mlir/IR/Operation.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Regex.h"
 
+#define DEBUG_TYPE "dialect"
+
 using namespace mlir;
 using namespace detail;
 
@@ -27,12 +30,28 @@
 //===----------------------------------------------------------------------===//
 
 void DialectRegistry::addDialectInterface(
-    StringRef dialectName, InterfaceAllocatorFunction allocator) {
+    StringRef dialectName, TypeID interfaceTypeID,
+    InterfaceAllocatorFunction allocator) {
   assert(allocator && "unexpected null interface allocation function");
   auto it = registry.find(dialectName.str());
   assert(it != registry.end() &&
          "adding an interface for an unregistered dialect");
-  interfaces[it->second.first].push_back(allocator);
+
+  // Bail out if the interface with the given ID is already in the registry for
+  // the given dialect. We expect a small number (dozens) of interfaces so a
+  // linear search is fine here.
+  auto &dialectInterfaces = interfaces[it->second.first];
+  for (const auto &kvp : dialectInterfaces) {
+    if (kvp.first == interfaceTypeID) {
+      LLVM_DEBUG(llvm::dbgs()
+                 << "[" DEBUG_TYPE
+                    "] repeated interface registration for dialect "
+                 << dialectName);
+      return;
+    }
+  }
+
+  dialectInterfaces.emplace_back(interfaceTypeID, allocator);
 }
 
 DialectAllocatorFunctionRef
@@ -59,8 +78,12 @@
   if (it == interfaces.end())
     return;
 
-  for (const InterfaceAllocatorFunction &createInterface : it->second)
-    dialect->addInterface(createInterface(dialect));
+  // Add an interface if it is not already present.
+  for (const auto &kvp : it->second) {
+    if (dialect->getRegisteredInterface(kvp.first))
+      continue;
+    dialect->addInterface(kvp.second(dialect));
+  }
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/mlir/unittests/IR/DialectTest.cpp b/mlir/unittests/IR/DialectTest.cpp
--- a/mlir/unittests/IR/DialectTest.cpp
+++ b/mlir/unittests/IR/DialectTest.cpp
@@ -94,4 +94,29 @@
   EXPECT_TRUE(secondTestDialectInterface != nullptr);
 }
 
+TEST(Dialect, RepeatedDelayedRegistration) {
+  // Set up the delayed registration.
+  DialectRegistry registry;
+  registry.insert<TestDialect>();
+  registry.addDialectInterface<TestDialect, TestDialectInterface>();
+  MLIRContext context(registry);
+
+  // Load the TestDialect and check that the interface got registered for it.
+  auto *testDialect = context.getOrLoadDialect<TestDialect>();
+  ASSERT_TRUE(testDialect != nullptr);
+  auto *testDialectInterface =
+      testDialect->getRegisteredInterface<TestDialectInterfaceBase>();
+  EXPECT_TRUE(testDialectInterface != nullptr);
+
+  // Try adding the same dialect interface again and check that we don't crash
+  // on repeated interface registration.
+  DialectRegistry secondRegistry;
+  secondRegistry.insert<TestDialect>();
+  secondRegistry.addDialectInterface<TestDialect, TestDialectInterface>();
+  context.appendDialectRegistry(secondRegistry);
+  testDialectInterface =
+      testDialect->getRegisteredInterface<TestDialectInterfaceBase>();
+  EXPECT_TRUE(testDialectInterface != nullptr);
+}
+
 } // end namespace