diff --git a/expat/expat.pc.cmake b/expat/expat.pc.cmake
index da7a0549..56da4137 100644
--- a/expat/expat.pc.cmake
+++ b/expat/expat.pc.cmake
@@ -10,3 +10,4 @@ URL: https://libexpat.github.io/
 Libs: -L${libdir} -l$<TARGET_PROPERTY:expat,pkgconfig_$<LOWER_CASE:$<CONFIG>>_output_name>
 Libs.private: $<TARGET_PROPERTY:expat,pkgconfig_libm>
 Cflags: -I${includedir}
+Cflags.private: -DXML_STATIC
diff --git a/expat/expat.pc.in b/expat/expat.pc.in
index db080653..a53ab118 100644
--- a/expat/expat.pc.in
+++ b/expat/expat.pc.in
@@ -10,3 +10,4 @@ URL: https://libexpat.github.io/
 Libs: -L${libdir} -l@PACKAGE_NAME@
 Libs.private: @LIBM@
 Cflags: -I${includedir}
+Cflags.private: -DXML_STATIC