diff --git a/lib/rules/no-unused-vars.js b/lib/rules/no-unused-vars.js
index 4dc6dc2bab3..b4ba8361d44 100644
--- a/lib/rules/no-unused-vars.js
+++ b/lib/rules/no-unused-vars.js
@@ -308,6 +308,10 @@ module.exports = {
         function getRhsNode(ref, prevRhsNode) {
             const id = ref.identifier;
             const parent = id.parent;
+
+            if (!parent) {
+                return null;
+            }
             const grandparent = parent.parent;
             const refScope = ref.from.variableScope;
             const varScope = ref.resolved.scope.variableScope;
@@ -321,6 +325,9 @@ module.exports = {
                 return prevRhsNode;
             }
 
+            if (!grandparent) {
+                return null;
+            }
             if (parent.type === "AssignmentExpression" &&
                 grandparent.type === "ExpressionStatement" &&
                 id === parent.left &&
@@ -415,8 +422,15 @@ module.exports = {
         function isReadForItself(ref, rhsNode) {
             const id = ref.identifier;
             const parent = id.parent;
+
+            if (!parent) {
+                return false;
+            }
             const grandparent = parent.parent;
 
+            if (!grandparent) {
+                return false;
+            }
             return ref.isRead() && (
 
                 // self update. e.g. `a += 1`, `a++`
@@ -444,6 +458,10 @@ module.exports = {
         function isForInRef(ref) {
             let target = ref.identifier.parent;
 
+            // For empty loop body
+            if (!target) {
+                return false;
+            }
 
             // "for (var ...) { return; }"
             if (target.type === "VariableDeclarator") {
@@ -565,6 +583,10 @@ module.exports = {
 
                         if (type === "Parameter") {
 
+                            if (!def.node.parent) {
+                                continue;
+                            }
+
                             // skip any setter argument
                             if ((def.node.parent.type === "Property" || def.node.parent.type === "MethodDefinition") && def.node.parent.kind === "set") {
                                 continue;