diff --git a/src/main/java/com/google/devtools/build/lib/rules/config/ConfigSetting.java b/src/main/java/com/google/devtools/build/lib/rules/config/ConfigSetting.java
index cc06b86450274f..cb70244ed28eea 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/config/ConfigSetting.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/config/ConfigSetting.java
@@ -497,10 +497,14 @@ static UserDefinedFlagMatch fromAttributeValueAndPrerequisites(
         } else if (target.satisfies(BuildSettingProvider.REQUIRE_BUILD_SETTING_PROVIDER)) {
           // build setting
           BuildSettingProvider provider = target.getProvider(BuildSettingProvider.class);
-          Object configurationValue =
-              optionDetails.getOptionValue(specifiedLabel) != null
-                  ? optionDetails.getOptionValue(specifiedLabel)
-                  : provider.getDefaultValue();
+
+          Object configurationValue;
+          if (optionDetails.getOptionValue(provider.getLabel()) != null) {
+            configurationValue = optionDetails.getOptionValue(provider.getLabel());
+          } else {
+            configurationValue = provider.getDefaultValue();
+          }
+
           Object convertedSpecifiedValue;
           try {
             // We don't need to supply a base package or repo mapping for the conversion here,
diff --git a/src/test/java/com/google/devtools/build/lib/rules/LabelBuildSettingTest.java b/src/test/java/com/google/devtools/build/lib/rules/LabelBuildSettingTest.java
index 5500ab253823fc..013cc9a02580d3 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/LabelBuildSettingTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/LabelBuildSettingTest.java
@@ -116,6 +116,35 @@ public void testLabelFlag_set() throws Exception {
     assertThat(b.get("value")).isEqualTo("command_line_value");
   }
 
+  @Test
+  public void withSelectThroughAlias() throws Exception {
+    writeRulesBzl("flag");
+    scratch.file(
+        "test/BUILD",
+        "load('//test:rules.bzl', 'my_rule', 'simple_rule')",
+        "simple_rule(name = 'default', value = 'default_value')",
+        "simple_rule(name = 'command_line', value = 'command_line_value')",
+        "label_flag(name = 'my_label_flag', build_setting_default = ':default')",
+        "alias(name = 'my_label_flag_alias', actual = ':my_label_flag')",
+        "config_setting(",
+        "    name = 'is_default_label',",
+        "    flag_values = {':my_label_flag_alias': '//test:default'}",
+        ")",
+        "simple_rule(name = 'selector', value = select({':is_default_label': 'valid'}))");
+
+    useConfiguration();
+    getConfiguredTarget("//test:selector");
+    assertNoEvents();
+
+    reporter.removeHandler(failFastHandler);
+    useConfiguration(
+        ImmutableMap.of(
+            "//test:my_label_flag", Label.parseCanonicalUnchecked("//test:command_line")));
+    getConfiguredTarget("//test:selector");
+    assertContainsEvent(
+        "configurable attribute \"value\" in //test:selector doesn't match this configuration");
+  }
+
   @Test
   public void withSelect() throws Exception {
     writeRulesBzl("flag");
diff --git a/src/test/java/com/google/devtools/build/lib/rules/config/ConfigSettingTest.java b/src/test/java/com/google/devtools/build/lib/rules/config/ConfigSettingTest.java
index b4bf5b70672996..5bb6968eb13617 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/config/ConfigSettingTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/config/ConfigSettingTest.java
@@ -2177,6 +2177,27 @@ public void ruleLicensesUsed() throws Exception {
     assertThat(getLicenses("//test:match")).containsExactly(LicenseType.NONE);
   }
 
+  @Test
+  public void aliasedStarlarkFlag() throws Exception {
+    scratch.file(
+        "test/flagdef.bzl",
+        "def _impl(ctx):",
+        "    return []",
+        "my_flag = rule(",
+        "    implementation = _impl,",
+        "    build_setting = config.string(flag = True))");
+
+    scratch.file(
+        "test/BUILD",
+        "load('//test:flagdef.bzl', 'my_flag')",
+        "my_flag(name = 'flag', build_setting_default = 'default')",
+        "alias(name = 'alias', actual = ':flag')",
+        "config_setting(name = 'alias_setting', flag_values = {':alias': 'specified'})");
+
+    useConfiguration(ImmutableMap.of("//test:flag", "specified"));
+    assertThat(getConfigMatchingProviderResultAsBoolean("//test:alias_setting")).isTrue();
+  }
+
   @Test
   public void simpleStarlarkFlag() throws Exception {
     scratch.file(