diff --git a/clang-tools-extra/clang-tidy/readability/ContainerContainsCheck.cpp b/clang-tools-extra/clang-tidy/readability/ContainerContainsCheck.cpp
index 05d4c87bc73ce..61f6a703257d6 100644
--- a/clang-tools-extra/clang-tidy/readability/ContainerContainsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/ContainerContainsCheck.cpp
@@ -8,7 +8,9 @@
 
 #include "ContainerContainsCheck.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/Expr.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
 
 using namespace clang::ast_matchers;
 
@@ -30,9 +32,15 @@ void ContainerContainsCheck::registerMatchers(MatchFinder *Finder) {
               ofClass(cxxRecordDecl(HasContainsMatchingParamType)))))
           .bind("call");
 
+  const auto Literal0 = integerLiteral(equals(0));
+  const auto Literal1 = integerLiteral(equals(1));
+
   const auto FindCall =
       cxxMemberCallExpr(
-          argumentCountIs(1),
+          anyOf(argumentCountIs(1),
+                allOf(argumentCountIs(2), // string::find takes two arguments
+                      hasArgument(1, anyOf(cxxDefaultArgExpr(),
+                                           ignoringParenImpCasts(Literal0))))),
           callee(cxxMethodDecl(
               hasName("find"),
               hasParameter(0, hasType(hasUnqualifiedDesugaredType(
@@ -48,8 +56,8 @@ void ContainerContainsCheck::registerMatchers(MatchFinder *Finder) {
                         // before EndCall so 'parameterType' is properly bound.
                         ofClass(cxxRecordDecl(HasContainsMatchingParamType)))));
 
-  const auto Literal0 = integerLiteral(equals(0));
-  const auto Literal1 = integerLiteral(equals(1));
+  const auto StringNpos = anyOf(declRefExpr(to(varDecl(hasName("npos")))),
+                                memberExpr(member(hasName("npos"))));
 
   auto AddSimpleMatcher = [&](auto Matcher) {
     Finder->addMatcher(
@@ -94,12 +102,14 @@ void ContainerContainsCheck::registerMatchers(MatchFinder *Finder) {
       binaryOperator(hasLHS(Literal1), hasOperatorName(">"), hasRHS(CountCall))
           .bind("negativeComparison"));
 
-  // Find membership tests based on `find() == end()`.
+  // Find membership tests based on `find() == end()` or `find() == npos`.
   AddSimpleMatcher(
-      binaryOperator(hasOperatorName("!="), hasOperands(FindCall, EndCall))
+      binaryOperator(hasOperatorName("!="),
+                     hasOperands(FindCall, anyOf(EndCall, StringNpos)))
           .bind("positiveComparison"));
   AddSimpleMatcher(
-      binaryOperator(hasOperatorName("=="), hasOperands(FindCall, EndCall))
+      binaryOperator(hasOperatorName("=="),
+                     hasOperands(FindCall, anyOf(EndCall, StringNpos)))
           .bind("negativeComparison"));
 }
 
diff --git a/clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/string b/clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/string
index 0c160bc182b6e..b1a3f40c10f18 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/string
+++ b/clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/string
@@ -50,12 +50,16 @@ struct basic_string {
   size_type find(const _Type& str, size_type pos = 0) const;
   size_type find(const C* s, size_type pos = 0) const;
   size_type find(const C* s, size_type pos, size_type n) const;
+  size_type find(C ch, size_type pos = 0) const;
 
   size_type rfind(const _Type& str, size_type pos = npos) const;
   size_type rfind(const C* s, size_type pos, size_type count) const;
   size_type rfind(const C* s, size_type pos = npos) const;
   size_type rfind(C ch, size_type pos = npos) const;
 
+  bool contains(const C *s) const;
+  bool contains(C s) const;
+
   _Type& insert(size_type pos, const _Type& str);
   _Type& insert(size_type pos, const C* s);
   _Type& insert(size_type pos, const C* s, size_type n);
@@ -104,6 +108,9 @@ struct basic_string_view {
   size_type rfind(const C* s, size_type pos, size_type count) const;
   size_type rfind(const C* s, size_type pos = npos) const;
 
+  bool contains(const C *s) const;
+  bool contains(C s) const;
+
   constexpr bool starts_with(basic_string_view sv) const noexcept;
   constexpr bool starts_with(C ch) const noexcept;
   constexpr bool starts_with(const C* s) const;
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/container-contains.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/container-contains.cpp
index 9a9b233e07229..4fa2a378cff2c 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/container-contains.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/container-contains.cpp
@@ -1,4 +1,7 @@
-// RUN: %check_clang_tidy -std=c++20-or-later %s readability-container-contains %t
+// RUN: %check_clang_tidy -std=c++20-or-later %s readability-container-contains %t -- \
+// RUN:   -- -isystem %clang_tidy_headers
+
+#include <string>
 
 // Some *very* simplified versions of `map` etc.
 namespace std {
@@ -29,6 +32,8 @@ struct multimap {
   bool contains(const Key &K) const;
 };
 
+
+
 } // namespace std
 
 // Check that we detect various common ways to check for membership
@@ -453,3 +458,29 @@ void testOperandPermutations(std::map<int, int>& Map) {
   // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use 'contains' to check for membership [readability-container-contains]
   // CHECK-FIXES: if (!Map.contains(0)) {};
 }
+
+void testStringNops(std::string Str, std::string SubStr, std::string_view StrView) {
+  if (Str.find("test") == std::string::npos) {};
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use 'contains' to check for membership [readability-container-contains]
+  // CHECK-FIXES: if (!Str.contains("test")) {};
+
+  if (Str.find('c') != std::string::npos) {};
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use 'contains' to check for membership [readability-container-contains]
+  // CHECK-FIXES: if (Str.contains('c')) {};
+
+  if (Str.find('c') != Str.npos) {};
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use 'contains' to check for membership [readability-container-contains]
+  // CHECK-FIXES: if (Str.contains('c')) {};
+
+  if (StrView.find("test") == std::string::npos) {};
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use 'contains' to check for membership [readability-container-contains]
+  // CHECK-FIXES: if (!StrView.contains("test")) {};
+
+  if (StrView.find('c') != std::string::npos) {};
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use 'contains' to check for membership [readability-container-contains]
+  // CHECK-FIXES: if (StrView.contains('c')) {};
+
+  if (StrView.find('c') != StrView.npos) {};
+  // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use 'contains' to check for membership [readability-container-contains]
+  // CHECK-FIXES: if (StrView.contains('c')) {};
+}