diff --git a/intern/cycles/blender/python.cpp b/intern/cycles/blender/python.cpp
index a0441c2e2c8..ea41b12bd42 100644
--- a/intern/cycles/blender/python.cpp
+++ b/intern/cycles/blender/python.cpp
@@ -615,14 +615,12 @@ static PyObject *osl_update_node_func(PyObject * /*self*/, PyObject *args)
 
     if (!found_existing) {
       /* Create new socket. */
-      BL::NodeSocket b_sock = (param->isoutput) ? b_node.outputs.create(b_data,
-                                                                        socket_type.c_str(),
-                                                                        param_label.c_str(),
-                                                                        param->name.c_str()) :
-                                                  b_node.inputs.create(b_data,
-                                                                       socket_type.c_str(),
-                                                                       param_label.c_str(),
-                                                                       param->name.c_str());
+      BL::NodeSocket b_sock =
+          (param->isoutput) ?
+              b_node.outputs.create(
+                  b_data, socket_type.c_str(), param_label.c_str(), param->name.c_str(), false) :
+              b_node.inputs.create(
+                  b_data, socket_type.c_str(), param_label.c_str(), param->name.c_str(), false);
 
       /* set default value */
       if (data_type == BL::NodeSocket::type_VALUE) {
diff --git a/scripts/templates_py/custom_nodes.py b/scripts/templates_py/custom_nodes.py
index f6fe0979ac1..bf2886fd00f 100644
--- a/scripts/templates_py/custom_nodes.py
+++ b/scripts/templates_py/custom_nodes.py
@@ -99,7 +99,7 @@ class MyCustomNode(MyCustomTreeNode, Node):
     def init(self, context):
         self.inputs.new('CustomSocketType', "Hello")
         self.inputs.new('NodeSocketFloat', "World")
-        self.inputs.new('NodeSocketVector', "!")
+        self.inputs.new('NodeSocketVector', "!", use_multi_input=True)
 
         self.outputs.new('NodeSocketColor', "How")
         self.outputs.new('NodeSocketColor', "are")
diff --git a/source/blender/makesrna/intern/rna_nodetree.cc b/source/blender/makesrna/intern/rna_nodetree.cc
index 479529155e7..cb35f43574c 100644
--- a/source/blender/makesrna/intern/rna_nodetree.cc
+++ b/source/blender/makesrna/intern/rna_nodetree.cc
@@ -2232,7 +2232,8 @@ static bNodeSocket *rna_Node_inputs_new(ID *id,
                                         ReportList *reports,
                                         const char *type,
                                         const char *name,
-                                        const char *identifier)
+                                        const char *identifier,
+                                        const bool use_multi_input)
 {
   if (!allow_changing_sockets(node)) {
     BKE_report(reports, RPT_ERROR, "Cannot add socket to built-in node");
@@ -2246,6 +2247,9 @@ static bNodeSocket *rna_Node_inputs_new(ID *id,
     BKE_report(reports, RPT_ERROR, "Unable to create socket");
   }
   else {
+    if (use_multi_input) {
+      sock->flag |= SOCK_MULTI_INPUT;
+    }
     ED_node_tree_propagate_change(nullptr, bmain, ntree);
     WM_main_add_notifier(NC_NODE | NA_EDITED, ntree);
   }
@@ -2259,13 +2263,19 @@ static bNodeSocket *rna_Node_outputs_new(ID *id,
                                          ReportList *reports,
                                          const char *type,
                                          const char *name,
-                                         const char *identifier)
+                                         const char *identifier,
+                                         const bool use_multi_input)
 {
   if (!allow_changing_sockets(node)) {
     BKE_report(reports, RPT_ERROR, "Cannot add socket to built-in node");
     return nullptr;
   }
 
+  if (use_multi_input) {
+    BKE_report(reports, RPT_ERROR, "Output sockets cannot be multi-input");
+    return nullptr;
+  }
+
   bNodeTree *ntree = reinterpret_cast<bNodeTree *>(id);
   bNodeSocket *sock = nodeAddSocket(ntree, node, SOCK_OUT, type, identifier, name);
 
@@ -9929,6 +9939,8 @@ static void rna_def_node_sockets_api(BlenderRNA *brna, PropertyRNA *cprop, int i
   parm = RNA_def_string(func, "name", nullptr, MAX_NAME, "Name", "");
   RNA_def_parameter_flags(parm, PropertyFlag(0), PARM_REQUIRED);
   RNA_def_string(func, "identifier", nullptr, MAX_NAME, "Identifier", "Unique socket identifier");
+  RNA_def_boolean(
+      func, "use_multi_input", false, "", "Make the socket a multi-input. Only valid for inputs");
   /* return value */
   parm = RNA_def_pointer(func, "socket", "NodeSocket", "", "New socket");
   RNA_def_function_return(func, parm);