diff --git a/mlir/docs/OpDefinitions.md b/mlir/docs/OpDefinitions.md
--- a/mlir/docs/OpDefinitions.md
+++ b/mlir/docs/OpDefinitions.md
@@ -1526,6 +1526,19 @@
 
 ## Appendix
 
+### Reporting deprecation
+
+Classes/defs can be marked as deprecated by using the `Deprecate` helper class,
+e.g.,
+
+```td
+def OpTraitA : NativeOpTrait<"OpTraitA">, Deprecated<"use `bar` instead">;
+```
+
+would result in marking `OpTraitA` as deprecated and mlir-tblgen can emit a
+warning (default) or error (depending on `-on-deprecated` flag) to make
+deprecated state known.
+
 ### Requirements and existing mechanisms analysis
 
 The op description should be as declarative as possible to allow a wide range of
diff --git a/mlir/include/mlir/IR/OpBase.td b/mlir/include/mlir/IR/OpBase.td
--- a/mlir/include/mlir/IR/OpBase.td
+++ b/mlir/include/mlir/IR/OpBase.td
@@ -38,6 +38,12 @@
   string result = r;
 }
 
+// Helper for marking deprecated classes or defs. To mark a def as deprecated,
+// mix in the `Deprecate` class with a reason.
+class Deprecated<string reason> {
+  string odsDeprecated = reason;
+}
+
 //===----------------------------------------------------------------------===//
 // Predicate definitions
 //===----------------------------------------------------------------------===//
diff --git a/mlir/test/mlir-tblgen/deprecation.td b/mlir/test/mlir-tblgen/deprecation.td
new file mode 100644
--- /dev/null
+++ b/mlir/test/mlir-tblgen/deprecation.td
@@ -0,0 +1,15 @@
+// RUN: not mlir-tblgen -on-deprecated=error -gen-op-decls -I %S/../../include -DERROR1 %s 2>&1 | FileCheck --check-prefix=ERROR1 %s
+
+include "mlir/IR/OpBase.td"
+
+def Test_Dialect : Dialect {
+  let name = "test_dialect";
+}
+
+#ifdef ERROR1
+def OpTraitA : NativeOpTrait<"OpTraitA">, Deprecated<"use `bar` instead">;
+
+// ERROR1: warning: Using deprecated def `OpTraitA`
+// ERROR1: use `bar` instead
+def OpTraitWithoutDependentTrait : Op<Test_Dialect, "default_value", [OpTraitA]> {}
+#endif
diff --git a/mlir/tools/mlir-tblgen/mlir-tblgen.cpp b/mlir/tools/mlir-tblgen/mlir-tblgen.cpp
--- a/mlir/tools/mlir-tblgen/mlir-tblgen.cpp
+++ b/mlir/tools/mlir-tblgen/mlir-tblgen.cpp
@@ -26,6 +26,15 @@
 using namespace llvm;
 using namespace mlir;
 
+enum DeprecatedAction { None, Warn, Error };
+llvm::cl::opt<DeprecatedAction> actionOnDeprecated(
+    "on-deprecated", llvm::cl::init(Warn),
+    llvm::cl::desc("Action to perform on deprecated def"),
+    llvm::cl::values(clEnumValN(DeprecatedAction::None, "none", "No action"),
+                     clEnumValN(DeprecatedAction::Warn, "warn", "Warn on use"),
+                     clEnumValN(DeprecatedAction::Error, "error",
+                                "Error on use")));
+
 static llvm::ManagedStatic<std::vector<GenInfo>> generatorRegistry;
 
 mlir::GenRegistration::GenRegistration(StringRef arg, StringRef description,
@@ -62,9 +71,80 @@
 // Generator to invoke.
 const mlir::GenInfo *generator;
 
+// Returns if there is a use of `init` in `record`.
+bool findUse(Record &record, Init *init,
+             llvm::DenseMap<Record *, bool> &known) {
+  auto it = known.find(&record);
+  if (it != known.end())
+    return it->second;
+
+  auto memoize = [&](bool val) {
+    known[&record] = val;
+    return val;
+  };
+
+  for (const RecordVal &val : record.getValues()) {
+    Init *valInit = val.getValue();
+    if (valInit == init)
+      return true;
+    if (auto *di = dyn_cast<DefInit>(valInit)) {
+      if (findUse(*di->getDef(), init, known))
+        return memoize(true);
+    } else if (auto *di = dyn_cast<DagInit>(valInit)) {
+      for (Init *arg : di->getArgs())
+        if (auto *di = dyn_cast<DefInit>(arg))
+          if (findUse(*di->getDef(), init, known))
+            return memoize(true);
+    } else if (ListInit *li = dyn_cast<ListInit>(valInit)) {
+      for (Init *jt : li->getValues())
+        if (jt == init)
+          return memoize(true);
+    }
+  }
+  return memoize(false);
+}
+
+void warnOfDeprecatedUses(RecordKeeper &records) {
+  // This performs a direct check for any def marked as deprecated and then
+  // finds all uses of deprecated def. Deprecated defs are not expected to be
+  // either numerous or long lived.
+  bool deprecatedDefsFounds = false;
+  for (auto &it : records.getDefs()) {
+    const RecordVal *r = it.second->getValue("odsDeprecated");
+    if (!r || !r->getValue())
+      continue;
+
+    llvm::DenseMap<Record *, bool> hasUse;
+    if (auto *si = dyn_cast<StringInit>(r->getValue())) {
+      for (auto &jt : records.getDefs()) {
+        // Skip anonymous defs.
+        if (jt.second->isAnonymous())
+          continue;
+        // Skip all outside main file to avoid flagging redundantly.
+        unsigned buf =
+            SrcMgr.FindBufferContainingLoc(jt.second->getLoc().front());
+        if (buf != SrcMgr.getMainFileID())
+          continue;
+
+        if (findUse(*jt.second, it.second->getDefInit(), hasUse)) {
+          PrintWarning(jt.second->getLoc(),
+                       "Using deprecated def `" + it.first + "`");
+          PrintNote(si->getAsUnquotedString());
+          deprecatedDefsFounds = true;
+        }
+      }
+    }
+  }
+  if (deprecatedDefsFounds && actionOnDeprecated == DeprecatedAction::Error)
+    PrintFatalNote("Error'ing out due to deprecated defs");
+}
+
 // TableGenMain requires a function pointer so this function is passed in which
 // simply wraps the call to the generator.
 static bool mlirTableGenMain(raw_ostream &os, RecordKeeper &records) {
+  if (actionOnDeprecated != DeprecatedAction::None)
+    warnOfDeprecatedUses(records);
+
   if (!generator) {
     os << records;
     return false;