diff --git a/app/imports/parser/grammar.js b/app/imports/parser/grammar.js
index 01336eb1..c1672285 100644
--- a/app/imports/parser/grammar.js
+++ b/app/imports/parser/grammar.js
@@ -13,6 +13,7 @@ function id(x) { return x[0]; }
   import RollNode from '/imports/parser/parseTree/RollNode.js';
   import SymbolNode from '/imports/parser/parseTree/SymbolNode.js';
   import UnaryOperatorNode from '/imports/parser/parseTree/UnaryOperatorNode.js';
+  import NotOperatorNode from '/imports/parser/parseTree/NotOperatorNode.js';
 
 	import moo from 'moo';
 
@@ -37,6 +38,7 @@ function id(x) { return x[0]; }
     ternaryOperator: ['?', ':'],
     multiplicativeOperator: ['*', '/'],
     exponentOperator: ['^'],
+    notOperator: ['!'],
     additiveOperator: ['+', '-'],
     andOperator: ['&', '&&'],
     orOperator: ['|', '||'],
@@ -81,7 +83,9 @@ let ParserRules = [
     {"name": "exponentExpression", "symbols": ["callExpression", "_", (lexer.has("exponentOperator") ? {type: "exponentOperator"} : exponentOperator), "_", "exponentExpression"], "postprocess": d => operator(d, 'exponent')},
     {"name": "exponentExpression", "symbols": ["unaryExpression"], "postprocess": id},
     {"name": "unaryExpression", "symbols": [(lexer.has("additiveOperator") ? {type: "additiveOperator"} : additiveOperator), "_", "unaryExpression"], "postprocess": d => new UnaryOperatorNode({operator: d[0].value, right: d[2]})},
-    {"name": "unaryExpression", "symbols": ["callExpression"], "postprocess": id},
+    {"name": "unaryExpression", "symbols": ["notExpression"], "postprocess": id},
+    {"name": "notExpression", "symbols": [(lexer.has("notOperator") ? {type: "notOperator"} : notOperator), "_", "notExpression"], "postprocess": d => new NotOperatorNode({right: d[2]})},
+    {"name": "notExpression", "symbols": ["callExpression"], "postprocess": id},
     {"name": "callExpression", "symbols": ["name", "_", "arguments"], "postprocess": 
         d => new CallNode ({functionName: d[0].name, args: d[2]})
           },
diff --git a/app/imports/parser/grammar.ne b/app/imports/parser/grammar.ne
index f2039bc1..7f768c39 100644
--- a/app/imports/parser/grammar.ne
+++ b/app/imports/parser/grammar.ne
@@ -11,6 +11,7 @@
   import RollNode from '/imports/parser/parseTree/RollNode.js';
   import SymbolNode from '/imports/parser/parseTree/SymbolNode.js';
   import UnaryOperatorNode from '/imports/parser/parseTree/UnaryOperatorNode.js';
+  import NotOperatorNode from '/imports/parser/parseTree/NotOperatorNode.js';
 
 	import moo from 'moo';
 
@@ -35,6 +36,7 @@
     ternaryOperator: ['?', ':'],
     multiplicativeOperator: ['*', '/'],
     exponentOperator: ['^'],
+    notOperator: ['!'],
     additiveOperator: ['+', '-'],
     andOperator: ['&', '&&'],
     orOperator: ['|', '||'],
@@ -105,6 +107,10 @@ exponentExpression ->
 
 unaryExpression ->
   %additiveOperator _ unaryExpression {% d => new UnaryOperatorNode({operator: d[0].value, right: d[2]})%}
+| notExpression {% id %}
+
+notExpression ->
+  %notOperator _ notExpression {% d => new NotOperatorNode({right: d[2]})%}
 | callExpression {% id %}
 
 callExpression ->
diff --git a/app/imports/parser/parseTree/NotOperatorNode.js b/app/imports/parser/parseTree/NotOperatorNode.js
new file mode 100644
index 00000000..e1ef4f62
--- /dev/null
+++ b/app/imports/parser/parseTree/NotOperatorNode.js
@@ -0,0 +1,27 @@
+import ParseNode from '/imports/parser/parseTree/ParseNode.js';
+import ConstantNode from '/imports/parser/parseTree/ConstantNode.js';
+
+export default class NotOperatorNode extends ParseNode {
+  constructor({right}) {
+		super(...arguments);
+    this.right = right;
+  }
+  resolve(fn, scope, context){
+    let rightNode = this.right[fn](scope, context);
+    if (!(rightNode instanceof ConstantNode)){
+      return new NotOperatorNode({
+        right: rightNode,
+      });
+    }
+    let right = rightNode.value;
+    let result = !right;
+    return new ConstantNode({
+      value: result,
+      type: typeof result,
+    });
+  }
+  toString(){
+    let {right} = this;
+    return `!${right.toString()}`;
+  }
+}
diff --git a/app/imports/parser/parseTree/OperatorNode.js b/app/imports/parser/parseTree/OperatorNode.js
index 8d609f41..376dddc5 100644
--- a/app/imports/parser/parseTree/OperatorNode.js
+++ b/app/imports/parser/parseTree/OperatorNode.js
@@ -13,7 +13,7 @@ export default class OperatorNode extends ParseNode {
     let leftNode = this.left[fn](scope, context);
     let rightNode = this.right[fn](scope, context);
     let left, right;
-    if (leftNode.type !== 'number' || rightNode.type !== 'number'){
+    if (!(leftNode instanceof ConstantNode) || !(rightNode instanceof ConstantNode)){
       return new OperatorNode({
         left: leftNode,
         right: rightNode,