diff --git a/clang-tools-extra/clang-tidy/bugprone/NotNullTerminatedResultCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/NotNullTerminatedResultCheck.cpp
index cba29b949fefd..1b1fbe97e9358 100644
--- a/clang-tools-extra/clang-tidy/bugprone/NotNullTerminatedResultCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/NotNullTerminatedResultCheck.cpp
@@ -177,7 +177,7 @@ static bool isDestBasedOnGivenLength(const MatchFinder::MatchResult &Result) {
   StringRef LengthExprStr =
       exprToStr(Result.Nodes.getNodeAs<Expr>(LengthExprName), Result).trim();
 
-  return DestCapacityExprStr != "" && LengthExprStr != "" &&
+  return !DestCapacityExprStr.empty() && !LengthExprStr.empty() &&
          DestCapacityExprStr.contains(LengthExprStr);
 }
 
diff --git a/clang-tools-extra/clang-tidy/bugprone/ReservedIdentifierCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/ReservedIdentifierCheck.cpp
index fb04e6e0fa936..6eefde369c59e 100644
--- a/clang-tools-extra/clang-tidy/bugprone/ReservedIdentifierCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/ReservedIdentifierCheck.cpp
@@ -104,7 +104,7 @@ static std::optional<std::string> getUnderscoreCapitalFixup(StringRef Name) {
 static bool startsWithUnderscoreInGlobalNamespace(StringRef Name,
                                                   bool IsInGlobalNamespace,
                                                   bool IsMacro) {
-  return !IsMacro && IsInGlobalNamespace && Name.size() >= 1 && Name[0] == '_';
+  return !IsMacro && IsInGlobalNamespace && !Name.empty() && Name[0] == '_';
 }
 
 static std::optional<std::string>
diff --git a/clang-tools-extra/clang-tidy/bugprone/SuspiciousIncludeCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/SuspiciousIncludeCheck.cpp
index 49293ab727af4..43d53f0b6020a 100644
--- a/clang-tools-extra/clang-tidy/bugprone/SuspiciousIncludeCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/SuspiciousIncludeCheck.cpp
@@ -101,7 +101,7 @@ void SuspiciousIncludePPCallbacks::InclusionDirective(
   for (const auto &HFE : Check.HeaderFileExtensions) {
     SmallString<128> GuessedFileName(FileName);
     llvm::sys::path::replace_extension(GuessedFileName,
-                                       (HFE.size() ? "." : "") + HFE);
+                                       (!HFE.empty() ? "." : "") + HFE);
 
     OptionalFileEntryRef File =
         PP->LookupFile(DiagLoc, GuessedFileName, IsAngled, nullptr, nullptr,
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/MisleadingCaptureDefaultByValueCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/MisleadingCaptureDefaultByValueCheck.cpp
index 138f4bf6b19c2..87e1b05802763 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/MisleadingCaptureDefaultByValueCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/MisleadingCaptureDefaultByValueCheck.cpp
@@ -50,7 +50,7 @@ static std::string createReplacementText(const LambdaExpr *Lambda) {
   llvm::raw_string_ostream Stream(Replacement);
 
   auto AppendName = [&](llvm::StringRef Name) {
-    if (Replacement.size() != 0) {
+    if (!Replacement.empty()) {
       Stream << ", ";
     }
     if (Lambda->getCaptureDefault() == LCD_ByRef && Name != "this") {
@@ -68,7 +68,7 @@ static std::string createReplacementText(const LambdaExpr *Lambda) {
       AppendName("this");
     }
   }
-  if (Replacement.size() &&
+  if (!Replacement.empty() &&
       Lambda->explicit_capture_begin() != Lambda->explicit_capture_end()) {
     // Add back separator if we are adding explicit capture variables.
     Stream << ", ";
diff --git a/clang-tools-extra/clang-tidy/modernize/UseConstraintsCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseConstraintsCheck.cpp
index 951cc2f9903ba..74074180b5a9f 100644
--- a/clang-tools-extra/clang-tidy/modernize/UseConstraintsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/UseConstraintsCheck.cpp
@@ -353,7 +353,7 @@ static std::vector<FixItHint> handleReturnType(const FunctionDecl *Function,
 
   SmallVector<const Expr *, 3> ExistingConstraints;
   Function->getAssociatedConstraints(ExistingConstraints);
-  if (ExistingConstraints.size() > 0) {
+  if (!ExistingConstraints.empty()) {
     // FIXME - Support adding new constraints to existing ones. Do we need to
     // consider subsumption?
     return {};
@@ -401,7 +401,7 @@ handleTrailingTemplateType(const FunctionTemplateDecl *FunctionTemplate,
 
   SmallVector<const Expr *, 3> ExistingConstraints;
   Function->getAssociatedConstraints(ExistingConstraints);
-  if (ExistingConstraints.size() > 0) {
+  if (!ExistingConstraints.empty()) {
     // FIXME - Support adding new constraints to existing ones. Do we need to
     // consider subsumption?
     return {};
diff --git a/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp b/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
index d240d8d244ef9..7d4c7d4448e84 100644
--- a/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
@@ -672,13 +672,13 @@ std::string IdentifierNamingCheck::HungarianNotation::getEnumPrefix(
       if (!Splitter.match(Substr, &Groups))
         break;
 
-      if (Groups[2].size() > 0) {
+      if (!Groups[2].empty()) {
         Words.push_back(Groups[1]);
         Substr = Substr.substr(Groups[0].size());
-      } else if (Groups[3].size() > 0) {
+      } else if (!Groups[3].empty()) {
         Words.push_back(Groups[3]);
         Substr = Substr.substr(Groups[0].size() - Groups[4].size());
-      } else if (Groups[5].size() > 0) {
+      } else if (!Groups[5].empty()) {
         Words.push_back(Groups[5]);
         Substr = Substr.substr(Groups[0].size() - Groups[6].size());
       }
@@ -913,13 +913,13 @@ std::string IdentifierNamingCheck::fixupWithCase(
       if (!Splitter.match(Substr, &Groups))
         break;
 
-      if (Groups[2].size() > 0) {
+      if (!Groups[2].empty()) {
         Words.push_back(Groups[1]);
         Substr = Substr.substr(Groups[0].size());
-      } else if (Groups[3].size() > 0) {
+      } else if (!Groups[3].empty()) {
         Words.push_back(Groups[3]);
         Substr = Substr.substr(Groups[0].size() - Groups[4].size());
-      } else if (Groups[5].size() > 0) {
+      } else if (!Groups[5].empty()) {
         Words.push_back(Groups[5]);
         Substr = Substr.substr(Groups[0].size() - Groups[6].size());
       }
diff --git a/clang-tools-extra/clang-tidy/utils/ExceptionAnalyzer.cpp b/clang-tools-extra/clang-tidy/utils/ExceptionAnalyzer.cpp
index f1f1cc3b294d1..6ae46e2b1262a 100644
--- a/clang-tools-extra/clang-tidy/utils/ExceptionAnalyzer.cpp
+++ b/clang-tools-extra/clang-tidy/utils/ExceptionAnalyzer.cpp
@@ -19,7 +19,7 @@ void ExceptionAnalyzer::ExceptionInfo::registerException(
 
 void ExceptionAnalyzer::ExceptionInfo::registerExceptions(
     const Throwables &Exceptions) {
-  if (Exceptions.size() == 0)
+  if (Exceptions.empty())
     return;
   Behaviour = State::Throwing;
   ThrownExceptions.insert(Exceptions.begin(), Exceptions.end());
@@ -404,7 +404,7 @@ bool ExceptionAnalyzer::ExceptionInfo::filterByCatch(
     ThrownExceptions.erase(T);
 
   reevaluateBehaviour();
-  return TypesToDelete.size() > 0;
+  return !TypesToDelete.empty();
 }
 
 ExceptionAnalyzer::ExceptionInfo &
@@ -437,7 +437,7 @@ void ExceptionAnalyzer::ExceptionInfo::clear() {
 }
 
 void ExceptionAnalyzer::ExceptionInfo::reevaluateBehaviour() {
-  if (ThrownExceptions.size() == 0)
+  if (ThrownExceptions.empty())
     if (ContainsUnknown)
       Behaviour = State::Unknown;
     else