diff --git a/CMakeLists.txt b/CMakeLists.txt
index cde194a020..f4731bd85b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -272,7 +272,7 @@ endif()
 include(cmake/OpenCVCompilerOptions.cmake REQUIRED)
 
 # In case of Makefiles if the user does not setup CMAKE_BUILD_TYPE, assume it's Release:
-if(CMAKE_GENERATOR MATCHES "Makefiles" AND "${CMAKE_BUILD_TYPE}" STREQUAL "")
+if(CMAKE_GENERATOR MATCHES "Makefiles|Ninja" AND "${CMAKE_BUILD_TYPE}" STREQUAL "")
   set(CMAKE_BUILD_TYPE Release)
 endif()
 
diff --git a/cmake/OpenCVModule.cmake b/cmake/OpenCVModule.cmake
index beb2fb1d04..9c21c732f8 100644
--- a/cmake/OpenCVModule.cmake
+++ b/cmake/OpenCVModule.cmake
@@ -509,7 +509,7 @@ macro(ocv_add_precompiled_headers the_target)
             add_native_precompiled_header(${the_target} ${pch_header})
         elseif(CMAKE_GENERATOR MATCHES Xcode)
             add_native_precompiled_header(${the_target} ${pch_header})
-        elseif(CMAKE_COMPILER_IS_GNUCXX AND CMAKE_GENERATOR MATCHES Makefiles)
+        elseif(CMAKE_COMPILER_IS_GNUCXX AND CMAKE_GENERATOR MATCHES "Makefiles|Ninja")
             add_precompiled_header(${the_target} ${pch_header})
         endif()
     endif()