diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index 8d0256ba07..dff61776bd 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -57,6 +57,7 @@
 #ifndef OPENSSL_NO_ECDH
 #include <openssl/ec.h>
 #endif
+#include <openssl/x509.h>
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
diff --git a/src/interfaces/libpq/fe-secure-openssl.c b/src/interfaces/libpq/fe-secure-openssl.c
index ac2842cd06..ecd68061a2 100644
--- a/src/interfaces/libpq/fe-secure-openssl.c
+++ b/src/interfaces/libpq/fe-secure-openssl.c
@@ -58,6 +58,7 @@
 #ifdef USE_SSL_ENGINE
 #include <openssl/engine.h>
 #endif
+#include <openssl/x509.h>
 #include <openssl/x509v3.h>
 
 static bool verify_peer_name_matches_certificate(PGconn *);