diff --git a/intern/cycles/blender/blender_object.cpp b/intern/cycles/blender/blender_object.cpp
index 54128cf82fc..619cdf98fa1 100644
--- a/intern/cycles/blender/blender_object.cpp
+++ b/intern/cycles/blender/blender_object.cpp
@@ -560,10 +560,12 @@ void BlenderSync::sync_objects(BL::Depsgraph &b_depsgraph,
   if (!cancel && !motion) {
     sync_background_light(b_v3d, use_portal);
 
-    /* handle removed data and modified pointers */
+    /* Handle removed data and modified pointers, as this may free memory, delete Nodes in the
+     * right order to ensure that dependant data is freed after their users. Objects should be
+     * freed before particle systems and geometries. */
     light_map.post_sync();
-    geometry_map.post_sync();
     object_map.post_sync();
+    geometry_map.post_sync();
     particle_system_map.post_sync();
   }
 
diff --git a/intern/cycles/graph/node.cpp b/intern/cycles/graph/node.cpp
index c926f6ab8ef..c5b4bb471bb 100644
--- a/intern/cycles/graph/node.cpp
+++ b/intern/cycles/graph/node.cpp
@@ -367,9 +367,17 @@ void Node::copy_value(const SocketType &socket, const Node &other, const SocketT
       case SocketType::TRANSFORM_ARRAY:
         copy_array<Transform>(this, socket, &other, other_socket);
         break;
-      case SocketType::NODE_ARRAY:
+      case SocketType::NODE_ARRAY: {
         copy_array<void *>(this, socket, &other, other_socket);
+
+        array<Node *> &node_array = get_socket_value<array<Node *>>(this, socket);
+
+        for (Node *node: node_array) {
+          node->reference();
+        }
+
         break;
+      }
       default:
         assert(0);
         break;
@@ -379,6 +387,14 @@ void Node::copy_value(const SocketType &socket, const Node &other, const SocketT
     const void *src = ((char *)&other) + other_socket.struct_offset;
     void *dst = ((char *)this) + socket.struct_offset;
     memcpy(dst, src, socket.size());
+
+    if (socket.type == SocketType::NODE) {
+      Node *node = get_socket_value<Node *>(this, socket);
+
+      if (node) {
+        node->reference();
+      }
+    }
   }
 }
 
@@ -773,6 +789,26 @@ void Node::set_owner(const NodeOwner *owner_)
   owner = owner_;
 }
 
+void Node::dereference_all_used_nodes()
+{
+  foreach (const SocketType &socket, type->inputs) {
+    if (socket.type == SocketType::NODE) {
+      Node *node = get_socket_value<Node *>(this, socket);
+
+      if (node) {
+        node->dereference();
+      }
+    }
+    else if (socket.type == SocketType::NODE_ARRAY) {
+      const array<Node *> &nodes = get_socket_value<array<Node *>>(this, socket);
+
+      for (Node *node : nodes) {
+        node->dereference();
+      }
+    }
+  }
+}
+
 bool Node::socket_is_modified(const SocketType &input) const
 {
   return (socket_modified & input.modified_flag_bit) != 0;
@@ -803,6 +839,25 @@ template<typename T> void Node::set_if_different(const SocketType &input, T valu
   socket_modified |= input.modified_flag_bit;
 }
 
+void Node::set_if_different(const SocketType &input, Node *value)
+{
+  if (get_socket_value<Node *>(this, input) == value) {
+    return;
+  }
+
+  Node *old_node = get_socket_value<Node *>(this, input);
+  if (old_node) {
+    old_node->dereference();
+  }
+
+  if (value) {
+    value->reference();
+  }
+
+  get_socket_value<Node *>(this, input) = value;
+  socket_modified |= input.modified_flag_bit;
+}
+
 template<typename T> void Node::set_if_different(const SocketType &input, array<T> &value)
 {
   if (!socket_is_modified(input)) {
@@ -815,6 +870,27 @@ template<typename T> void Node::set_if_different(const SocketType &input, array<
   socket_modified |= input.modified_flag_bit;
 }
 
+void Node::set_if_different(const SocketType &input, array<Node *> &value)
+{
+  if (!socket_is_modified(input)) {
+    if (get_socket_value<array<Node *>>(this, input) == value) {
+      return;
+    }
+  }
+
+  array<Node *> &old_nodes = get_socket_value<array<Node *>>(this, input);
+  for (Node *old_node : old_nodes) {
+    old_node->dereference();
+  }
+
+  for (Node *new_node : value) {
+    new_node->reference();
+  }
+
+  get_socket_value<array<Node *>>(this, input).steal_data(value);
+  socket_modified |= input.modified_flag_bit;
+}
+
 void Node::print_modified_sockets() const
 {
   printf("Node : %s\n", name.c_str());
diff --git a/intern/cycles/graph/node.h b/intern/cycles/graph/node.h
index 2fc9a1e0281..aa365baeccd 100644
--- a/intern/cycles/graph/node.h
+++ b/intern/cycles/graph/node.h
@@ -177,8 +177,32 @@ struct Node {
   const NodeOwner *get_owner() const;
   void set_owner(const NodeOwner *owner_);
 
+  int reference_count() const
+  {
+    return ref_count;
+  }
+
+  void reference()
+  {
+    ref_count += 1;
+  }
+
+  void dereference()
+  {
+    ref_count -= 1;
+  }
+
+  /* Set the reference count to zero. This should only be called when we know for sure that the
+   * Node is not used by anyone else. For now, this is only the case when "deleting" shaders, as
+   * they are never actually deleted. */
+  void clear_reference_count()
+  {
+    ref_count = 0;
+  }
+
  protected:
   const NodeOwner *owner;
+  int ref_count{0};
 
   template<typename T> static T &get_socket_value(const Node *node, const SocketType &socket)
   {
@@ -189,7 +213,19 @@ struct Node {
 
   template<typename T> void set_if_different(const SocketType &input, T value);
 
+  /* Explicit overload for Node sockets so we can handle reference counting. The old Node is
+   * dereferenced, and the new one is referenced. */
+  void set_if_different(const SocketType &input, Node *value);
+
   template<typename T> void set_if_different(const SocketType &input, array<T> &value);
+
+  /* Explicit overload for Node sockets so we can handle reference counting. The old Nodes are
+   * dereferenced, and the new ones are referenced. */
+  void set_if_different(const SocketType &input, array<Node *> &value);
+
+  /* Call this function in derived classes' destructors to ensure that used Nodes are dereferenced
+   * properly. */
+  void dereference_all_used_nodes();
 };
 
 CCL_NAMESPACE_END
diff --git a/intern/cycles/render/background.cpp b/intern/cycles/render/background.cpp
index f0a779da012..b925e755434 100644
--- a/intern/cycles/render/background.cpp
+++ b/intern/cycles/render/background.cpp
@@ -59,6 +59,7 @@ Background::Background() : Node(get_node_type())
 
 Background::~Background()
 {
+  dereference_all_used_nodes();
 }
 
 void Background::device_update(Device *device, DeviceScene *dscene, Scene *scene)
diff --git a/intern/cycles/render/geometry.cpp b/intern/cycles/render/geometry.cpp
index bd2b8164cbb..aac5af06e9f 100644
--- a/intern/cycles/render/geometry.cpp
+++ b/intern/cycles/render/geometry.cpp
@@ -79,6 +79,7 @@ Geometry::Geometry(const NodeType *node_type, const Type type)
 
 Geometry::~Geometry()
 {
+  dereference_all_used_nodes();
   delete bvh;
 }
 
diff --git a/intern/cycles/render/light.cpp b/intern/cycles/render/light.cpp
index 858b177b69c..9b975daff0b 100644
--- a/intern/cycles/render/light.cpp
+++ b/intern/cycles/render/light.cpp
@@ -159,6 +159,7 @@ NODE_DEFINE(Light)
 
 Light::Light() : Node(get_node_type())
 {
+  dereference_all_used_nodes();
 }
 
 void Light::tag_update(Scene *scene)
diff --git a/intern/cycles/render/scene.cpp b/intern/cycles/render/scene.cpp
index 38e8d9145dc..dca545fa56c 100644
--- a/intern/cycles/render/scene.cpp
+++ b/intern/cycles/render/scene.cpp
@@ -143,21 +143,27 @@ void Scene::free_memory(bool final)
   delete bvh;
   bvh = NULL;
 
-  foreach (Shader *s, shaders)
-    delete s;
-  /* delete procedurals before other types as they may hold pointers to those types */
+  /* The order of deletion is important to make sure data is freed based on possible dependencies
+   * as the Nodes' reference counts are decremented in the destructors:
+   *
+   * - Procedurals can create and hold pointers to any other types.
+   * - Objects can hold pointers to Geometries and ParticleSystems
+   * - Lights and Geometries can hold pointers to Shaders.
+   *
+   * Similarly, we first delete all nodes and their associated device data, and then the managers
+   * and their associated device data.
+   */
   foreach (Procedural *p, procedurals)
     delete p;
-  foreach (Geometry *g, geometry)
-    delete g;
   foreach (Object *o, objects)
     delete o;
-  foreach (Light *l, lights)
-    delete l;
+  foreach (Geometry *g, geometry)
+    delete g;
   foreach (ParticleSystem *p, particle_systems)
     delete p;
+  foreach (Light *l, lights)
+    delete l;
 
-  shaders.clear();
   geometry.clear();
   objects.clear();
   lights.clear();
@@ -169,7 +175,25 @@ void Scene::free_memory(bool final)
     film->device_free(device, &dscene, this);
     background->device_free(device, &dscene);
     integrator->device_free(device, &dscene, true);
+  }
 
+  if (final) {
+    delete camera;
+    delete dicing_camera;
+    delete film;
+    delete background;
+    delete integrator;
+  }
+
+  /* Delete Shaders after every other nodes to ensure that we do not try to decrement the reference
+   * count on some dangling pointer. */
+  foreach (Shader *s, shaders)
+    delete s;
+
+  shaders.clear();
+
+  /* Now that all nodes have been deleted, we can safely delete managers and device data. */
+  if (device) {
     object_manager->device_free(device, &dscene, true);
     geometry_manager->device_free(device, &dscene, true);
     shader_manager->device_free(device, &dscene, this);
@@ -189,11 +213,6 @@ void Scene::free_memory(bool final)
 
   if (final) {
     delete lookup_tables;
-    delete camera;
-    delete dicing_camera;
-    delete film;
-    delete background;
-    delete integrator;
     delete object_manager;
     delete geometry_manager;
     delete shader_manager;