diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -252,8 +252,6 @@ if(FUZZ)
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=address,fuzzer-no-link -fsanitize-coverage=edge,indirect-calls")
 endif()
 
-add_definitions(-DBORINGSSL_IMPLEMENTATION)
-
 if(BUILD_SHARED_LIBS)
   add_definitions(-DBORINGSSL_SHARED_LIBRARY)
   # Enable position-independent code globally. This is needed because
@@ -563,7 +561,7 @@ if(APPLE)
 endif()
 
 add_library(pki ${PKI_SOURCES})
-target_compile_definitions(pki PRIVATE _BORINGSSL_LIBPKI_)
+target_compile_definitions(pki PRIVATE _BORINGSSL_LIBPKI_ BORINGSSL_IMPLEMENTATION)
 target_link_libraries(pki crypto)
 
 add_executable(pki_test ${PKI_TEST_SOURCES})
diff --git a/crypto/CMakeLists.txt b/crypto/CMakeLists.txt
--- a/crypto/CMakeLists.txt
+++ b/crypto/CMakeLists.txt
@@ -294,6 +294,7 @@ add_library(
   $<TARGET_OBJECTS:fipsmodule>
   ${CRYPTO_FIPS_OBJECTS}
 )
+target_compile_definitions(crypto PRIVATE BORINGSSL_IMPLEMENTATION)
 if(OPENSSL_ASM)
   target_sources(crypto PRIVATE ${CRYPTO_SOURCES_ASM})
 endif()
diff --git a/ssl/CMakeLists.txt b/ssl/CMakeLists.txt
--- a/ssl/CMakeLists.txt
+++ b/ssl/CMakeLists.txt
@@ -39,6 +39,7 @@ add_library(
   tls13_enc.cc
   tls13_server.cc
 )
+target_compile_definitions(ssl PRIVATE BORINGSSL_IMPLEMENTATION)
 # Although libssl also provides headers that require an include directory, the
 # flag is already specified by libcrypto, so we omit target_include_directories
 # here.