diff --git a/internal/codeguard/checks/quality/quality_defensive.go b/internal/codeguard/checks/quality/quality_defensive.go
index 827303a..110d609 100644
--- a/internal/codeguard/checks/quality/quality_defensive.go
+++ b/internal/codeguard/checks/quality/quality_defensive.go
@@ -318,8 +318,6 @@ func nullableParamGuarded(loweredBody string, name string) bool {
 		name + " != null",
 		name + " == nullptr",
 		name + " != nullptr",
-		"typeof " + name + " === ",
-		"typeof " + name + " == ",
 	}
 	if containsAny(loweredBody, guards) {
 		return true
@@ -356,7 +354,14 @@ func nullableUseLine(fn precisionFunction, name string) int {
 }
 
 func nullableStatementUsesOnlyNullSafeOperators(statement string, name string) bool {
-	return containsAny(statement, []string{name + "?.", name + "?.[", name + " ??"})
+	if containsAny(statement, []string{name + "?.", name + "?.[", name + " ??"}) {
+		return true
+	}
+	// A typeof check only narrows the value on the branch controlled by that
+	// check. Do not treat an arbitrary typeof occurrence elsewhere in the
+	// function as a null guard.
+	quotedName := regexp.QuoteMeta(name)
+	return regexp.MustCompile(`typeof\s+` + quotedName + `\s*={2,3}\s*['"](?:string|number|boolean|bigint|symbol|function)['"]\s*\?[^:]*\b` + quotedName + `(?:\.|\[)`).MatchString(statement)
 }
 
 func firstUseLine(fn precisionFunction, name string) int {
diff --git a/tests/checks/quality_precision_followup_retune_test.go b/tests/checks/quality_precision_followup_retune_test.go
index dca7d5d..373e5cd 100644
--- a/tests/checks/quality_precision_followup_retune_test.go
+++ b/tests/checks/quality_precision_followup_retune_test.go
@@ -406,6 +406,26 @@ func TestDefensiveNullAssumptionCreditsTypeScriptNarrowing(t *testing.T) {
 	assertCodeQualityRuleAbsentForPath(t, report, "defensive.null-assumption", "null-narrowing.ts:16")
 }
 
+func TestDefensiveNullAssumptionRejectsUnsafeTypeofGuards(t *testing.T) {
+	dir := t.TempDir()
+	writeFile(t, filepath.Join(dir, "packages/api/src/lib/unsafe-typeof.ts"), strings.Join([]string{
+		"export function objectCheck(user: User | null) {",
+		"  if (typeof user === 'object') return user.email;",
+		"}",
+		"export function lateCheck(user: User | null) {",
+		"  const email = user.email;",
+		"  if (typeof user === 'string') return '';",
+		"  return email;",
+		"}",
+		"interface User { email: string }",
+	}, "\n"))
+
+	report := runQualityPrecisionScan(t, qualityPrecisionConfigForLanguage(dir, "typescript"))
+
+	assertCodeQualityRulePresentForPathWithMessage(t, report, "defensive.null-assumption", "unsafe-typeof.ts:2")
+	assertCodeQualityRulePresentForPathWithMessage(t, report, "defensive.null-assumption", "unsafe-typeof.ts:5")
+}
+
 func TestDefensiveBoundaryInputSkipsTypedInternalDTOs(t *testing.T) {
 	dir := t.TempDir()
 	writeFile(t, filepath.Join(dir, "packages/api/src/routers/internal-dtos.ts"), strings.Join([]string{