diff --git a/algo/detectors/bmon/BmonReadoutConfig.h b/algo/detectors/bmon/BmonReadoutConfig.h
index 5cfa0e09ea1d9ff5890adc9ae4c99daa06057bc1..b8f7d568bf6ea979660abad6a4a6e8e9713925f7 100644
--- a/algo/detectors/bmon/BmonReadoutConfig.h
+++ b/algo/detectors/bmon/BmonReadoutConfig.h
@@ -11,6 +11,7 @@
 #ifndef ALGO_DETECTORS_BMON_BMONREADOUTCONFIG_H
 #define ALGO_DETECTORS_BMON_BMONREADOUTCONFIG_H
 
+#include <cstddef>
 #include <cstdint>
 #include <map>
 #include <vector>
diff --git a/algo/detectors/tof/TofReadoutConfig.h b/algo/detectors/tof/TofReadoutConfig.h
index 30b40104fef1b8d135e79a46fdffdfa7bd5d3008..2c648ad21638acedf8ba07ee135abeecbba3386b 100644
--- a/algo/detectors/tof/TofReadoutConfig.h
+++ b/algo/detectors/tof/TofReadoutConfig.h
@@ -5,6 +5,7 @@
 #ifndef ALGO_DETECTORS_TOF_TOFREADOUTCONFIG_H
 #define ALGO_DETECTORS_TOF_TOFREADOUTCONFIG_H
 
+#include <cstddef>
 #include <cstdint>
 #include <map>
 #include <vector>