diff --git a/mlir/docs/Diagnostics.md b/mlir/docs/Diagnostics.md
--- a/mlir/docs/Diagnostics.md
+++ b/mlir/docs/Diagnostics.md
@@ -108,7 +108,8 @@
 ```
 
 Operations attached to a diagnostic will be printed in generic form if the
-severity level is `Error`, otherwise custom operation printers will be used.
+severity level is `Error` or `Warning`, otherwise custom operation printers will
+be used.
 ```c++
 // `anotherOp` will be printed in generic form,
 // e.g. %3 = "arith.addf"(%arg4, %2) : (f32, f32) -> f32
diff --git a/mlir/docs/OpDefinitions.md b/mlir/docs/OpDefinitions.md
--- a/mlir/docs/OpDefinitions.md
+++ b/mlir/docs/OpDefinitions.md
@@ -606,9 +606,9 @@
 Custom verifiers should avoid printing operations using custom operation
 printers, because they require the printed operation (and sometimes its parent
 operation) to be verified first. In particular, when emitting diagnostics,
-custom verifiers should use the `Error` severity level, which prints operations
-in generic form by default, and avoid using lower severity levels (`Note`,
-`Remark`, `Warning`).
+custom verifiers should use the `Error` or `Warning` severity level, which print
+operations in generic form by default, and avoid using lower severity levels
+(`Note`, `Remark`).
 
 ### Declarative Assembly Format
 
diff --git a/mlir/lib/IR/Diagnostics.cpp b/mlir/lib/IR/Diagnostics.cpp
--- a/mlir/lib/IR/Diagnostics.cpp
+++ b/mlir/lib/IR/Diagnostics.cpp
@@ -127,7 +127,8 @@
                                            DiagnosticSeverity severity) {
   flags.useLocalScope();
   flags.elideLargeElementsAttrs();
-  if (severity == DiagnosticSeverity::Error)
+  if (severity == DiagnosticSeverity::Error ||
+      severity == DiagnosticSeverity::Warning)
     flags.printGenericOpForm();
   return flags;
 }