diff --git a/docs/Extensions.md b/docs/Extensions.md
index 67a087d..02276fb 100644
--- a/docs/Extensions.md
+++ b/docs/Extensions.md
@@ -122,6 +122,7 @@
   files are easier to write and use.
 * $ and \ edit descriptors are supported in FORMAT to suppress newline
   output on user prompts.
+* Tabs in format strings (not `FORMAT` statements) are allowed on output.
 * REAL and DOUBLE PRECISION variable and bounds in DO loops
 * Integer literals without explicit kind specifiers that are out of range
   for the default kind of INTEGER are assumed to have the least larger kind
diff --git a/runtime/format-implementation.h b/runtime/format-implementation.h
index b0ebcbc..a32bb8e 100644
--- a/runtime/format-implementation.h
+++ b/runtime/format-implementation.h
@@ -359,6 +359,10 @@
       context.AdvanceRecord(repeat && *repeat > 0 ? *repeat : 1);
     } else if (ch == '$' || ch == '\\') {
       context.mutableModes().nonAdvancing = true;
+    } else if (ch == '\t' || ch == '\v') {
+      // Tabs (extension)
+      // TODO: any other raw characters?
+      context.Emit(format_ + offset_ - 1, 1);
     } else {
       context.SignalError(IostatErrorInFormat,
           "Invalid character '%c' in FORMAT", static_cast<char>(ch));