diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -127,6 +127,9 @@
 Removed Compiler Flags
 -------------------------
 
+* ``-enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang`` has been removed.
+  It has not been needed to enable ``-ftrivial-auto-var-init=zero`` since Clang 16.
+
 Attribute Changes in Clang
 --------------------------
 - On X86, a warning is now emitted if a function with ``__attribute__((no_caller_saved_registers))``
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -272,12 +272,6 @@
 def mmpx : Flag<["-"], "mmpx">, Group<clang_ignored_legacy_options_Group>;
 def mno_mpx : Flag<["-"], "mno-mpx">, Group<clang_ignored_legacy_options_Group>;
 
-// Retired with clang-16.0, to provide a deprecation period; it should
-// be removed in Clang 18 or later.
-def enable_trivial_var_init_zero : Flag<["-"], "enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang">,
-  Flags<[NoArgumentUnused]>, Visibility<[ClangOption, CC1Option, CLOption]>,
-  Group<clang_ignored_legacy_options_Group>;
-
 // Group that ignores all gcc optimizations that won't be implemented
 def clang_ignored_gcc_optimization_f_Group : OptionGroup<
   "<clang_ignored_gcc_optimization_f_Group>">, Group<f_Group>, Flags<[Ignored]>;
diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c
--- a/clang/test/Driver/clang_f_opts.c
+++ b/clang/test/Driver/clang_f_opts.c
@@ -563,12 +563,9 @@
 // RUN: %clang -### -S -ftrivial-auto-var-init=uninitialized %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-UNINIT %s
 // RUN: %clang -### -S -ftrivial-auto-var-init=pattern %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-PATTERN %s
 // RUN: %clang -### -S -ftrivial-auto-var-init=zero %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-ZERO %s
-// RUN: %clang -### -S -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang \
-// RUN:   -ftrivial-auto-var-init=zero %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-ZERO-ENABLE-DEPRECATED %s
 // CHECK-TRIVIAL-UNINIT-NOT: hasn't been enabled
 // CHECK-TRIVIAL-PATTERN-NOT: hasn't been enabled
 // CHECK-TRIVIAL-ZERO-NOT: hasn't been enabled
-// CHECK-TRIVIAL-ZERO-ENABLE-DEPRECATED: has been deprecated
 
 // RUN: %clang -### -S -ftrivial-auto-var-init=pattern -ftrivial-auto-var-init-stop-after=1 %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-PATTERN-STOP-AFTER %s
 // RUN: %clang -### -S -ftrivial-auto-var-init=zero -ftrivial-auto-var-init-stop-after=1 %s 2>&1 | FileCheck -check-prefix=CHECK-TRIVIAL-ZERO-STOP-AFTER %s