diff --git a/include/compat/unistd.h b/include/compat/unistd.h
index 805c06e..6c83e76 100644
--- a/include/compat/unistd.h
+++ b/include/compat/unistd.h
@@ -27,6 +27,13 @@ unsigned int sleep(unsigned int seconds);
 
 #ifndef HAVE_GETENTROPY
 int getentropy(void *buf, size_t buflen);
+#else
+/*
+ * Solaris 11.3 adds getentropy(2), but defines the function in sys/random.h
+ */
+#if defined(__sun)
+#include <sys/random.h>
+#endif
 #endif
 
 #define pledge(request, paths) 0