diff --git a/redhat/applications/k3b/k3b.spec b/redhat/applications/k3b/k3b.spec
index 7d2da140f..39e494225 100644
--- a/redhat/applications/k3b/k3b.spec
+++ b/redhat/applications/k3b/k3b.spec
@@ -422,6 +422,10 @@ unset QTDIR QTINC QTLIB
 export PATH="%{tde_bindir}:${PATH}"
 export PKG_CONFIG_PATH="%{tde_libdir}/pkgconfig:${PKG_CONFIG_PATH}"
 
+%if 0%{?rhel} == 7
+RPM_OPT_FLAGS="${RPM_OPT_FLAGS} -std=c++11"
+%endif
+
 if ! rpm -E %%cmake|grep -q "cd build"; then
   %__mkdir_p build
   cd build