diff --git a/ReactAndroid/src/main/jni/first-party/fb/CMakeLists.txt b/ReactAndroid/src/main/jni/first-party/fb/CMakeLists.txt
index 7319e832fcff96..c3e3ecebbbd75b 100644
--- a/ReactAndroid/src/main/jni/first-party/fb/CMakeLists.txt
+++ b/ReactAndroid/src/main/jni/first-party/fb/CMakeLists.txt
@@ -21,6 +21,9 @@ add_compile_options(
         -Wno-error=unused-but-set-variable
         -DHAVE_POSIX_CLOCKS
 )
+if(${CMAKE_BUILD_TYPE} MATCHES Release)
+        add_compile_options(-DNDEBUG)
+endif()
 
 # Yogacore needs to link towards android and log from the NDK libs
 target_link_libraries(fb dl android log)
diff --git a/ReactCommon/hermes/executor/CMakeLists.txt b/ReactCommon/hermes/executor/CMakeLists.txt
index de74c65daea888..f63bd1e7d04f62 100644
--- a/ReactCommon/hermes/executor/CMakeLists.txt
+++ b/ReactCommon/hermes/executor/CMakeLists.txt
@@ -28,4 +28,10 @@ if(${CMAKE_BUILD_TYPE} MATCHES Debug)
                 PRIVATE
                 -DHERMES_ENABLE_DEBUGGER=1
         )
+else()
+        target_compile_options(
+                hermes_executor_common
+                PRIVATE
+                -DNDEBUG
+        )
 endif()
diff --git a/ReactCommon/jsc/CMakeLists.txt b/ReactCommon/jsc/CMakeLists.txt
index 2f387fa996f644..5db3ff62a01bbc 100644
--- a/ReactCommon/jsc/CMakeLists.txt
+++ b/ReactCommon/jsc/CMakeLists.txt
@@ -33,3 +33,7 @@ target_link_libraries(jscruntime
 # TODO: Remove this flag when ready.
 # Android has this enabled by default, but the flag is still needed for iOS.
 target_compile_options(jscruntime PRIVATE -DRN_FABRIC_ENABLED)
+
+if(${CMAKE_BUILD_TYPE} MATCHES Release)
+        target_compile_options(jscruntime PRIVATE -DNDEBUG)
+endif()
diff --git a/ReactCommon/react/debug/CMakeLists.txt b/ReactCommon/react/debug/CMakeLists.txt
index 620a1c54392c8c..ccfc69872e7340 100644
--- a/ReactCommon/react/debug/CMakeLists.txt
+++ b/ReactCommon/react/debug/CMakeLists.txt
@@ -22,3 +22,7 @@ add_library(react_debug SHARED ${react_debug_SRC})
 target_include_directories(react_debug PUBLIC ${REACT_COMMON_DIR})
 
 target_link_libraries(react_debug log folly_runtime)
+
+if(${CMAKE_BUILD_TYPE} MATCHES Release)
+        target_compile_options(react_debug PUBLIC -DNDEBUG)
+endif()
diff --git a/ReactCommon/react/debug/flags.h b/ReactCommon/react/debug/flags.h
index 62d1cc445746a1..dae3ecc4e51f81 100644
--- a/ReactCommon/react/debug/flags.h
+++ b/ReactCommon/react/debug/flags.h
@@ -10,7 +10,9 @@
 //
 // Enable REACT_NATIVE_DEBUG if NDEBUG is not defined.
 // Due to BUCK defaults in open-source, NDEBUG is always defined for all android
-// builds (if you build without BUCK, this isn't an issue). Thus we introduce
+// builds.
+// If you build in OSS with CMake, you will have -DNDEBUG set only for release
+// builds, therefore REACT_NATIVE_DEBUG will not be set. Here we introduce
 // REACT_NATIVE_DEBUG that we use internally instead of NDEBUG that we can
 // control and use as a more reliable xplat flag. For any build that doesn't
 // have NDEBUG defined, we enable REACT_NATIVE_DEBUG for convenience.