diff --git a/src/mplutils.h b/src/mplutils.h
index 8d4ae709e154..06a05337667e 100644
--- a/src/mplutils.h
+++ b/src/mplutils.h
@@ -18,6 +18,16 @@ typedef unsigned __int8   uint8_t;
 #    undef _XOPEN_SOURCE
 #endif
 
+// Prevent multiple conflicting definitions of swab from stdlib.h and unistd.h
+#if defined(__sun) || defined(sun)
+#if defined(_XPG4)
+#undef _XPG4
+#endif
+#if defined(_XPG3)
+#undef _XPG3
+#endif
+#endif
+
 #include <Python.h>
 
 #if PY_MAJOR_VERSION >= 3
diff --git a/src/numpy_cpp.h b/src/numpy_cpp.h
index 887ffe48aee7..d68a637bc117 100644
--- a/src/numpy_cpp.h
+++ b/src/numpy_cpp.h
@@ -25,6 +25,16 @@
 #    undef _XOPEN_SOURCE
 #endif
 
+// Prevent multiple conflicting definitions of swab from stdlib.h and unistd.h
+#if defined(__sun) || defined(sun)
+#if defined(_XPG4)
+#undef _XPG4
+#endif
+#if defined(_XPG3)
+#undef _XPG3
+#endif
+#endif
+
 #include <Python.h>
 #include <numpy/ndarrayobject.h>