diff --git a/ompi/mca/pml/ob1/pml_ob1_irecv.c b/ompi/mca/pml/ob1/pml_ob1_irecv.c
index 51ff68e643..88174dd8c8 100644
--- a/ompi/mca/pml/ob1/pml_ob1_irecv.c
+++ b/ompi/mca/pml/ob1/pml_ob1_irecv.c
@@ -28,6 +28,9 @@
 #include "pml_ob1_recvfrag.h"
 #include "ompi/peruse/peruse-internal.h"
 #include "ompi/message/message.h"
+#if HAVE_ALLOCA_H
+#include <alloca.h>
+#endif  /* HAVE_ALLOCA_H */
 
 int mca_pml_ob1_irecv_init(void *addr,
                            size_t count,
diff --git a/ompi/mca/pml/ob1/pml_ob1_isend.c b/ompi/mca/pml/ob1/pml_ob1_isend.c
index 0149df854b..1ebdfde839 100644
--- a/ompi/mca/pml/ob1/pml_ob1_isend.c
+++ b/ompi/mca/pml/ob1/pml_ob1_isend.c
@@ -26,6 +26,9 @@
 #include "pml_ob1_sendreq.h"
 #include "pml_ob1_recvreq.h"
 #include "ompi/peruse/peruse-internal.h"
+#if HAVE_ALLOCA_H
+#include <alloca.h>
+#endif  /* HAVE_ALLOCA_H */
 
 int mca_pml_ob1_isend_init(void *buf,
                            size_t count,