diff --git a/pkgs/development/compilers/llvm/5/lldb.nix b/pkgs/development/compilers/llvm/5/lldb.nix
index e0698e1dcf3d..e827f76231f1 100644
--- a/pkgs/development/compilers/llvm/5/lldb.nix
+++ b/pkgs/development/compilers/llvm/5/lldb.nix
@@ -1,5 +1,6 @@
 { stdenv
 , fetch
+, fetchpatch
 , cmake
 , zlib
 , ncurses
@@ -20,6 +21,15 @@ stdenv.mkDerivation {
 
   src = fetch "lldb" "05j2a63yzln43852nng8a7y47spzlyr1cvdmgmbxgd29c8r0bfkq";
 
+  patches = [
+    # Fix PythonString::GetString for >=python-3.7
+    (fetchpatch {
+      url = "https://github.com/llvm/llvm-project/commit/5457b426f5e15a29c0acc8af1a476132f8be2a36.patch";
+      sha256 = "1zbx4m0m8kbg0wq6740jcw151vb2pb1p25p401wiq8diqqagkjps";
+      stripLen = 1;
+    })
+  ];
+
   postPatch = ''
     # Fix up various paths that assume llvm and clang are installed in the same place
     sed -i 's,".*ClangConfig.cmake","${clang-unwrapped}/lib/cmake/clang/ClangConfig.cmake",' \
diff --git a/pkgs/development/compilers/llvm/6/lldb.nix b/pkgs/development/compilers/llvm/6/lldb.nix
index 80e298eaf8c0..629749e10f3c 100644
--- a/pkgs/development/compilers/llvm/6/lldb.nix
+++ b/pkgs/development/compilers/llvm/6/lldb.nix
@@ -1,5 +1,6 @@
 { stdenv
 , fetch
+, fetchpatch
 , cmake
 , zlib
 , ncurses
@@ -20,6 +21,15 @@ stdenv.mkDerivation {
 
   src = fetch "lldb" "05178zkyh84x32n91md6wm22lkzzrrfwa5cpmgzn0yrg3y2771bb";
 
+  patches = [
+    # Fix PythonString::GetString for >=python-3.7
+    (fetchpatch {
+      url = "https://github.com/llvm/llvm-project/commit/5457b426f5e15a29c0acc8af1a476132f8be2a36.patch";
+      sha256 = "1zbx4m0m8kbg0wq6740jcw151vb2pb1p25p401wiq8diqqagkjps";
+      stripLen = 1;
+    })
+  ];
+
   postPatch = ''
     # Fix up various paths that assume llvm and clang are installed in the same place
     sed -i 's,".*ClangConfig.cmake","${clang-unwrapped}/lib/cmake/clang/ClangConfig.cmake",' \