diff --git a/modules/audio_processing/beamformer/nonlinear_beamformer.h b/modules/audio_processing/beamformer/nonlinear_beamformer.h
index 76556e7a45..5b79dc467e 100644
--- a/modules/audio_processing/beamformer/nonlinear_beamformer.h
+++ b/modules/audio_processing/beamformer/nonlinear_beamformer.h
@@ -12,7 +12,9 @@
 #define MODULES_AUDIO_PROCESSING_BEAMFORMER_NONLINEAR_BEAMFORMER_H_
 
 // MSVC++ requires this to be set before any other includes to get M_PI.
+#ifndef _USE_MATH_DEFINES
 #define _USE_MATH_DEFINES
+#endif
 
 #include <math.h>
 
diff --git a/modules/audio_processing/include/audio_processing.h b/modules/audio_processing/include/audio_processing.h
index b750c6960e..ab9d2cda77 100644
--- a/modules/audio_processing/include/audio_processing.h
+++ b/modules/audio_processing/include/audio_processing.h
@@ -12,7 +12,9 @@
 #define MODULES_AUDIO_PROCESSING_INCLUDE_AUDIO_PROCESSING_H_
 
 // MSVC++ requires this to be set before any other includes to get M_PI.
+#ifndef _USE_MATH_DEFINES
 #define _USE_MATH_DEFINES
+#endif
 
 #include <math.h>
 #include <stddef.h>  // size_t