Index: clang-tidy/readability/FunctionSizeCheck.h
===================================================================
--- clang-tidy/readability/FunctionSizeCheck.h
+++ clang-tidy/readability/FunctionSizeCheck.h
@@ -28,7 +28,9 @@
 ///   * `BranchThreshold` - flag functions exceeding this number of control
 ///     statements. The default is `-1` (ignore the number of branches).
 ///   * `ParameterThreshold` - flag functions having a high number of parameters.
-///     The default is `6`.
+///     The default is `-1`.
+///   * `NestingThreshold` - flag compound statements which create next nesting
+///     level after `NestingThreshold`. The default is `10`.
 class FunctionSizeCheck : public ClangTidyCheck {
 public:
   FunctionSizeCheck(StringRef Name, ClangTidyContext *Context);
@@ -42,6 +44,7 @@
   const unsigned StatementThreshold;
   const unsigned BranchThreshold;
   const unsigned ParameterThreshold;
+  const unsigned NestingThreshold;
 };
 
 } // namespace readability
Index: clang-tidy/readability/FunctionSizeCheck.cpp
===================================================================
--- clang-tidy/readability/FunctionSizeCheck.cpp
+++ clang-tidy/readability/FunctionSizeCheck.cpp
@@ -38,6 +38,12 @@
       ++Info.Branches;
     // fallthrough
     case Stmt::CompoundStmtClass:
+      // if this is the exact compount statement that is right above the
+      // threshold, record the position
+      if (std::count_if(TrackedParent.begin(), TrackedParent.end(),
+                        [](bool Val) { return Val; }) == Info.NestingThreshold)
+        Info.NestingThresholders.push_back(Node->getLocStart());
+
       TrackedParent.push_back(true);
       break;
     default:
@@ -59,10 +65,12 @@
   }
 
   struct FunctionInfo {
-    FunctionInfo() : Lines(0), Statements(0), Branches(0) {}
-    unsigned Lines;
-    unsigned Statements;
-    unsigned Branches;
+    unsigned Lines = 0;
+    unsigned Statements = 0;
+    unsigned Branches = 0;
+
+    unsigned NestingThreshold = 0;
+    std::vector<SourceLocation> NestingThresholders;
   };
   FunctionInfo Info;
   std::vector<bool> TrackedParent;
@@ -73,13 +81,15 @@
       LineThreshold(Options.get("LineThreshold", -1U)),
       StatementThreshold(Options.get("StatementThreshold", 800U)),
       BranchThreshold(Options.get("BranchThreshold", -1U)),
-      ParameterThreshold(Options.get("ParameterThreshold", -1U)) {}
+      ParameterThreshold(Options.get("ParameterThreshold", -1U)),
+      NestingThreshold(Options.get("NestingThreshold", 10U)) {}
 
 void FunctionSizeCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
   Options.store(Opts, "LineThreshold", LineThreshold);
   Options.store(Opts, "StatementThreshold", StatementThreshold);
   Options.store(Opts, "BranchThreshold", BranchThreshold);
   Options.store(Opts, "ParameterThreshold", ParameterThreshold);
+  Options.store(Opts, "NestingThreshold", NestingThreshold);
 }
 
 void FunctionSizeCheck::registerMatchers(MatchFinder *Finder) {
@@ -90,6 +100,7 @@
   const auto *Func = Result.Nodes.getNodeAs<FunctionDecl>("func");
 
   FunctionASTVisitor Visitor;
+  Visitor.Info.NestingThreshold = NestingThreshold;
   Visitor.TraverseDecl(const_cast<FunctionDecl *>(Func));
   auto &FI = Visitor.Info;
 
@@ -138,6 +149,12 @@
          DiagnosticIDs::Note)
         << ActualNumberParameters << ParameterThreshold;
   }
+
+  for (const auto &CSPos : FI.NestingThresholders) {
+    diag(CSPos, "nesting level %0 starts here (threshold %1)",
+         DiagnosticIDs::Note)
+        << NestingThreshold + 1 << NestingThreshold;
+  }
 }
 
 } // namespace readability
Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -95,6 +95,11 @@
   Finds possible inefficient vector operations in for loops that may cause
   unnecessary memory reallocations.
   
+- Added `NestingThreshold` to `readability-function-size
+  <http://clang.llvm.org/extra/clang-tidy/checks/readability-function-size.html>`_ check
+
+  Finds compound statements which create next nesting level after `NestingThreshold` and emits a warning.
+
 - Added `ParameterThreshold` to `readability-function-size
   <http://clang.llvm.org/extra/clang-tidy/checks/readability-function-size.html>`_ check
 
Index: test/clang-tidy/readability-function-size.cpp
===================================================================
--- test/clang-tidy/readability-function-size.cpp
+++ test/clang-tidy/readability-function-size.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy %s readability-function-size %t -- -config='{CheckOptions: [{key: readability-function-size.LineThreshold, value: 0}, {key: readability-function-size.StatementThreshold, value: 0}, {key: readability-function-size.BranchThreshold, value: 0}, {key: readability-function-size.ParameterThreshold, value: 5}]}' -- -std=c++11
+// RUN: %check_clang_tidy %s readability-function-size %t -- -config='{CheckOptions: [{key: readability-function-size.LineThreshold, value: 0}, {key: readability-function-size.StatementThreshold, value: 0}, {key: readability-function-size.BranchThreshold, value: 0}, {key: readability-function-size.ParameterThreshold, value: 5}, {key: readability-function-size.NestingThreshold, value: 2}]}' -- -std=c++11
 
 // Bad formatting is intentional, don't run clang-format over the whole file!
 
@@ -59,3 +59,28 @@
 //
 // CHECK-MESSAGES: :[[@LINE-4]]:30: warning: function 'barx' exceeds recommended size/complexity
 // CHECK-MESSAGES: :[[@LINE-5]]:30: note: 2 statements (threshold 0)
+
+void baz0() { // 1
+  int a;
+  { // 2
+    int b;
+    { // 3
+      int c;
+      { // 4
+        int d;
+      }
+    }
+  }
+  { // 2
+    int e;
+  }
+  { // 2
+    { // 3
+      int j;
+    }
+  }
+}
+// CHECK-MESSAGES: :[[@LINE-20]]:6: warning: function 'baz0' exceeds recommended size/complexity
+// CHECK-MESSAGES: :[[@LINE-21]]:6: note: 6 statements (threshold 0)
+// CHECK-MESSAGES: :[[@LINE-18]]:5: note: nesting level 3 starts here (threshold 2)
+// CHECK-MESSAGES: :[[@LINE-8]]:5: note: nesting level 3 starts here (threshold 2)