diff --git a/src/main/java/com/google/devtools/build/lib/analysis/starlark/StarlarkTransition.java b/src/main/java/com/google/devtools/build/lib/analysis/starlark/StarlarkTransition.java
index 317225b133a4dd..0cf754541bcfd0 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/starlark/StarlarkTransition.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/starlark/StarlarkTransition.java
@@ -267,13 +267,16 @@ public static Map<String, BuildOptions> validate(
       Map<PackageValue.Key, PackageValue> buildSettingPackages,
       Map<String, BuildOptions> toOptions)
       throws TransitionException {
-    // collect settings changed during this transition and their types
+    // Collect settings changed during this transition and their types. This includes settings that
+    // were only used as inputs as to the transition and thus had their default values added to the
+    // fromOptions, which in case of a no-op transition directly end up in toOptions.
     Map<Label, Rule> changedSettingToRule = Maps.newHashMap();
     root.visit(
         (StarlarkTransitionVisitor)
             transition -> {
               ImmutableSet<Label> changedSettings =
-                  getRelevantStarlarkSettingsFromTransition(transition, Settings.OUTPUTS);
+                  getRelevantStarlarkSettingsFromTransition(
+                      transition, Settings.INPUTS_AND_OUTPUTS);
               for (Label setting : changedSettings) {
                 changedSettingToRule.put(
                     setting, getActual(buildSettingPackages, setting).getAssociatedRule());
diff --git a/src/test/java/com/google/devtools/build/lib/analysis/StarlarkAttrTransitionProviderTest.java b/src/test/java/com/google/devtools/build/lib/analysis/StarlarkAttrTransitionProviderTest.java
index 1d510d69b766da..39a8afe67c3f97 100644
--- a/src/test/java/com/google/devtools/build/lib/analysis/StarlarkAttrTransitionProviderTest.java
+++ b/src/test/java/com/google/devtools/build/lib/analysis/StarlarkAttrTransitionProviderTest.java
@@ -2249,4 +2249,165 @@ public void testNoPlatformChange() throws Exception {
     assertThat(getConfiguration(dep).getOptions().get(PlatformOptions.class).platforms)
         .containsExactly(Label.parseAbsoluteUnchecked("//platforms:my_platform"));
   }
+
+  @Test
+  public void testEffectiveNoopTransitionTrimsInputBuildSettings() throws Exception {
+    writeAllowlistFile();
+    scratch.file(
+        "test/starlark/rules.bzl",
+        "def _string_impl(ctx):",
+        "    return []",
+        "string_flag = rule(",
+        "    implementation = _string_impl,",
+        "    build_setting = config.string(flag = True),",
+        ")",
+        "def _no_op_transition_impl(settings, attr):",
+        "    return {",
+        "        '//test/starlark:input_and_output': settings['//test/starlark:input_and_output'],",
+        "        '//test/starlark:output_only': 'output_only_default',",
+        "    }",
+        "_no_op_transition = transition(",
+        "    implementation = _no_op_transition_impl,",
+        "    inputs = [",
+        "        '//test/starlark:input_only',",
+        "        '//test/starlark:input_and_output',",
+        "    ],",
+        "    outputs = [",
+        "        '//test/starlark:input_and_output',",
+        "        '//test/starlark:output_only',",
+        "    ],",
+        ")",
+        "def _apply_transition_impl(ctx):",
+        "    ctx.actions.symlink(",
+        "        output = ctx.outputs.out,",
+        "        target_file = ctx.file.target,",
+        "    )",
+        "    return [DefaultInfo(executable = ctx.outputs.out)]",
+        "apply_transition = rule(",
+        "    implementation = _apply_transition_impl,",
+        "    attrs = {",
+        "        'target': attr.label(",
+        "            cfg = _no_op_transition,",
+        "            allow_single_file = True,",
+        "        ),",
+        "        'out': attr.output(),",
+        "        '_allowlist_function_transition': attr.label(",
+        "            default = '//tools/allowlists/function_transition_allowlist',",
+        "        ),",
+        "    },",
+        "    executable = False,",
+        ")");
+    scratch.file(
+        "test/starlark/BUILD",
+        "load('//test/starlark:rules.bzl', 'apply_transition', 'string_flag')",
+        "",
+        "string_flag(",
+        "    name = 'input_only',",
+        "    build_setting_default = 'input_only_default',",
+        ")",
+        "string_flag(",
+        "    name = 'input_and_output',",
+        "    build_setting_default = 'input_and_output_default',",
+        ")",
+        "string_flag(",
+        "    name = 'output_only',",
+        "    build_setting_default = 'output_only_default',",
+        ")",
+        "cc_binary(",
+        "    name = 'main',",
+        "    srcs = ['main.cc'],",
+        ")",
+        "apply_transition(",
+        "    name = 'transitioned_main',",
+        "    target = ':main',",
+        "    out = 'main_out',",
+        ")");
+
+    update(
+        ImmutableList.of("//test/starlark:main", "//test/starlark:transitioned_main"),
+        /*keepGoing=*/ false,
+        LOADING_PHASE_THREADS,
+        /*doAnalysis=*/ true,
+        new EventBus());
+    assertNoEvents();
+  }
+
+  @Test
+  public void testExplicitNoopTransitionTrimsInputBuildSettings() throws Exception {
+    writeAllowlistFile();
+    scratch.file(
+        "test/starlark/rules.bzl",
+        "def _string_impl(ctx):",
+        "    return []",
+        "string_flag = rule(",
+        "    implementation = _string_impl,",
+        "    build_setting = config.string(flag = True),",
+        ")",
+        "def _no_op_transition_impl(settings, attr):",
+        "    return {}",
+        "_no_op_transition = transition(",
+        "    implementation = _no_op_transition_impl,",
+        "    inputs = [",
+        "        '//test/starlark:input_only',",
+        "        '//test/starlark:input_and_output',",
+        "    ],",
+        "    outputs = [",
+        "        '//test/starlark:input_and_output',",
+        "        '//test/starlark:output_only',",
+        "    ],",
+        ")",
+        "def _apply_transition_impl(ctx):",
+        "    ctx.actions.symlink(",
+        "        output = ctx.outputs.out,",
+        "        target_file = ctx.file.target,",
+        "    )",
+        "    return [DefaultInfo(executable = ctx.outputs.out)]",
+        "apply_transition = rule(",
+        "    implementation = _apply_transition_impl,",
+        "    attrs = {",
+        "        'target': attr.label(",
+        "            cfg = _no_op_transition,",
+        "            allow_single_file = True,",
+        "        ),",
+        "        'out': attr.output(),",
+        "        '_allowlist_function_transition': attr.label(",
+        "            default = '//tools/allowlists/function_transition_allowlist',",
+        "        ),",
+        "    },",
+        "    executable = False,",
+        ")");
+    scratch.file(
+        "test/starlark/BUILD",
+        "load('//test/starlark:rules.bzl', 'apply_transition', 'string_flag')",
+        "",
+        "string_flag(",
+        "    name = 'input_only',",
+        "    build_setting_default = 'input_only_default',",
+        ")",
+        "string_flag(",
+        "    name = 'input_and_output',",
+        "    build_setting_default = 'input_and_output_default',",
+        ")",
+        "string_flag(",
+        "    name = 'output_only',",
+        "    build_setting_default = 'output_only_default',",
+        ")",
+        "cc_binary(",
+        "    name = 'main',",
+        "    srcs = ['main.cc'],",
+        ")",
+        "apply_transition(",
+        "    name = 'transitioned_main',",
+        "    target = ':main',",
+        "    out = 'main_out',",
+        ")");
+
+    update(
+        ImmutableList.of("//test/starlark:main", "//test/starlark:transitioned_main"),
+        /*keepGoing=*/ false,
+        LOADING_PHASE_THREADS,
+        /*doAnalysis=*/ true,
+        new EventBus());
+    assertNoEvents();
+  }
 }