diff --git a/libraries/Microsoft.Bot.Builder.LanguageGeneration/Evaluator.cs b/libraries/Microsoft.Bot.Builder.LanguageGeneration/Evaluator.cs
index a507a91b50..92f9e55582 100644
--- a/libraries/Microsoft.Bot.Builder.LanguageGeneration/Evaluator.cs
+++ b/libraries/Microsoft.Bot.Builder.LanguageGeneration/Evaluator.cs
@@ -431,7 +431,7 @@ private object EvalExpression(string exp, ParserRuleContext expressionContext =
 
                 CheckExpressionResult(exp, error, result, templateName, lineContent, errorPrefix);
             }
-            else if (result == null && lgOptions.StrictMode != false)
+            else if (result == null && lgOptions.StrictMode != true)
             {
                 result = "null";
             }
diff --git a/libraries/Microsoft.Bot.Builder.LanguageGeneration/Expander.cs b/libraries/Microsoft.Bot.Builder.LanguageGeneration/Expander.cs
index a359daec5d..d0819a7c63 100644
--- a/libraries/Microsoft.Bot.Builder.LanguageGeneration/Expander.cs
+++ b/libraries/Microsoft.Bot.Builder.LanguageGeneration/Expander.cs
@@ -430,7 +430,7 @@ private List<string> EvalExpression(string exp, ParserRuleContext context = null
 
                 Evaluator.CheckExpressionResult(exp, error, result, templateName, lineContent, errorPrefix);
             }
-            else if (result == null && lgOptions.StrictMode == false)
+            else if (result == null && lgOptions.StrictMode != true)
             {
                 result = "null";
             }
diff --git a/tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Examples/EvaluationOptions/StrictModeFalse.lg b/tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Examples/EvaluationOptions/StrictModeFalse.lg
new file mode 100644
index 0000000000..573a44317a
--- /dev/null
+++ b/tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Examples/EvaluationOptions/StrictModeFalse.lg
@@ -0,0 +1,4 @@
+> !# @strict = false
+
+# StrictFalse
+- ${variable_not_defined}
\ No newline at end of file
diff --git a/tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Examples/EvaluationOptions/StrictModeTrue.lg b/tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Examples/EvaluationOptions/StrictModeTrue.lg
new file mode 100644
index 0000000000..92e5c90011
--- /dev/null
+++ b/tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Examples/EvaluationOptions/StrictModeTrue.lg
@@ -0,0 +1,4 @@
+> !# @strict = true
+
+# StrictTrue
+- ${variable_not_defined}
\ No newline at end of file
diff --git a/tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Microsoft.Bot.Builder.LanguageGeneration.Tests.csproj b/tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Microsoft.Bot.Builder.LanguageGeneration.Tests.csproj
index 2fc8f523b3..834a86f439 100644
--- a/tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Microsoft.Bot.Builder.LanguageGeneration.Tests.csproj
+++ b/tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Microsoft.Bot.Builder.LanguageGeneration.Tests.csproj
@@ -24,6 +24,7 @@
     <None Remove="Examples\EvaluationOptions\d3.lg" />
     <None Remove="Examples\EvaluationOptions\d4.lg" />
     <None Remove="Examples\EvaluationOptions\f4.lg" />
+    <None Remove="Examples\EvaluationOptions\StrictModeTrue.lg" />
     <None Remove="Examples\import\import3.lg" />
     <None Remove="Examples\1.lg" />
     <None Remove="Examples\2.lg" />
@@ -46,6 +47,7 @@
     <None Remove="Examples\LGOptionTest.lg" />
     <None Remove="Examples\MultilineTextForAdaptiveCard.lg" />
     <None Remove="Examples\NonAdaptiveCardActivity.lg" />
+    <None Remove="Examples\StrictModeFalse.lg" />
     <None Remove="Examples\switchcase.lg" />
     <None Remove="Examples\TemplateNameWithDot.lg" />
     <None Remove="Examples\TemplateRef.lg" />
@@ -161,6 +163,9 @@
     <Content Include="Examples\EvaluationOptions\f4.lg">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
+    <Content Include="Examples\EvaluationOptions\StrictModeTrue.lg">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
     <Content Include="Examples\ExpressionExtract.lg">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
@@ -170,6 +175,9 @@
     <Content Include="Examples\EvaluationOptions\LGOptionTest.lg">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
+    <Content Include="Examples\EvaluationOptions\StrictModeFalse.lg">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
     <Content Include="Examples\InjectionTest\common.lg">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
diff --git a/tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/TemplatesTest.cs b/tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/TemplatesTest.cs
index 8c7e8db81f..9a85848999 100644
--- a/tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/TemplatesTest.cs
+++ b/tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/TemplatesTest.cs
@@ -710,6 +710,20 @@ public void TestExpandTemplateWithEmptyListInStructuredLG()
             Assert.AreEqual(JObject.Parse(evaled[0].ToString())["inputhint"].ToString(), "ignoringInput");
         }
 
+        [TestMethod]
+        public void TestExpandTemplateWithStrictMode()
+        {
+            var templates = Templates.ParseFile(GetExampleFilePath("EvaluationOptions/StrictModeFalse.lg"));
+            
+            var evaled = templates.ExpandTemplate("StrictFalse");
+            Assert.AreEqual("null", evaled[0].ToString());
+
+            templates = Templates.ParseFile(GetExampleFilePath("EvaluationOptions/StrictModeTrue.lg"));
+
+            var exception = Assert.ThrowsException<Exception>(() => templates.ExpandTemplate("StrictTrue"));
+            Assert.IsTrue(exception.Message.Contains("'variable_not_defined' evaluated to null. [StrictTrue]  Error occurred when evaluating '-${variable_not_defined}'"));
+        }
+
         [TestMethod]
         public void TestEvalExpression()
         {