diff --git a/Docs/API.md b/Docs/API.md
index ae60b4090..7a59954d5 100644
--- a/Docs/API.md
+++ b/Docs/API.md
@@ -27,6 +27,7 @@ The ASP.NET Core API project template uses `dotnet new` to enable you to turn fe
 - **Title** - The name of the project which determines the assembly product name. If the Swagger feature is enabled, shows the title on the Swagger UI.
 - **Description** - A description of the project which determines the assembly description. If the Swagger feature is enabled, shows the description on the Swagger UI.
 - **Author** - The name of the author of the project which determines the assembly author and copyright information.
+- **TreatWarningsAsErrors** - Treat warnings as errors.
 - **HttpPort** - Port number to use for the HTTP endpoint in launchSettings.json.
 - **HttpsPort** - Port number to use for the HTTPS endpoint in launchSettings.json.
 
diff --git a/Docs/GraphQL.md b/Docs/GraphQL.md
index 324505d96..ba735b4ff 100644
--- a/Docs/GraphQL.md
+++ b/Docs/GraphQL.md
@@ -22,6 +22,7 @@ The ASP.NET Core GraphQL project template uses `dotnet new` to enable you to tur
 - **Title** - The name of the project which determines the assembly product name.
 - **Description** - A description of the project which determines the assembly description.
 - **Author** - The name of the author of the project which determines the assembly author and copyright information.
+- **TreatWarningsAsErrors** - Treat warnings as errors.
 - **HttpPort** - Port number to use for the HTTP endpoint in launchSettings.json.
 - **HttpsPort** - Port number to use for the HTTPS endpoint in launchSettings.json.
 
diff --git a/Source/Content/ApiTemplate/.template.config/dotnetcli.host.json b/Source/Content/ApiTemplate/.template.config/dotnetcli.host.json
index 9da35d4ae..2044f141d 100644
--- a/Source/Content/ApiTemplate/.template.config/dotnetcli.host.json
+++ b/Source/Content/ApiTemplate/.template.config/dotnetcli.host.json
@@ -19,6 +19,9 @@
     "AuthorXmlEncoded": {
       "isHidden": true
     },
+    "TreatWarningsAsErrors": {
+      "longName": "treat-warnings-as-errors"
+    },
     "Swagger": {
       "longName": "swagger"
     },
diff --git a/Source/Content/ApiTemplate/.template.config/template.json b/Source/Content/ApiTemplate/.template.config/template.json
index d28145c8b..40aad83f7 100644
--- a/Source/Content/ApiTemplate/.template.config/template.json
+++ b/Source/Content/ApiTemplate/.template.config/template.json
@@ -141,6 +141,13 @@
       "valueSource": "Author",
       "valueTransform": "xmlEncode"
     },
+    // TreatWarningsAsErrors
+    "TreatWarningsAsErrors": {
+      "type": "parameter",
+      "datatype": "bool",
+      "defaultValue": "true",
+      "description": "Treat warnings as errors."
+    },
 
     // Swagger
     "Swagger": {
diff --git a/Source/Content/ApiTemplate/ApiTemplate.csproj b/Source/Content/ApiTemplate/ApiTemplate.csproj
index bdbf72a29..1cef5b567 100644
--- a/Source/Content/ApiTemplate/ApiTemplate.csproj
+++ b/Source/Content/ApiTemplate/ApiTemplate.csproj
@@ -1,8 +1,8 @@
-<Project Sdk="Microsoft.NET.Sdk.Web">
+<Project Sdk="Microsoft.NET.Sdk.Web">
   <!--#if (AuthoringMode)-->
   <PropertyGroup>
     <!-- Modify these constants to enable/disable a feature to debug the template. Note that this only affects the C#. -->
-    <DefineConstants>$(DefineConstants);Kestrel;IIS;NGINX;Azure;ApplicationInsights;HealthCheck;HttpsEverywhere;HstsPreload;ForwardedHeaders;HostFiltering;ResponseCaching;ResponseCompression;CORS;HumansTxt;RobotsTxt;Swagger;Versioning;DataContractSerializer;CorrelationId</DefineConstants>
+    <DefineConstants>$(DefineConstants);TreatWarningsAsErrors;Kestrel;IIS;NGINX;Azure;ApplicationInsights;HealthCheck;HttpsEverywhere;HstsPreload;ForwardedHeaders;HostFiltering;ResponseCaching;ResponseCompression;CORS;HumansTxt;RobotsTxt;Swagger;Versioning;DataContractSerializer;CorrelationId</DefineConstants>
     <!-- Workaround to build this project: https://github.com/dotnet/templating/issues/1438 -->
     <ApplicationInsights>true</ApplicationInsights>
     <Azure>true</Azure>
@@ -32,6 +32,7 @@
     <!-- Enable tiered JIT compilation for better performance.
          See http://mattwarren.org/2017/12/15/How-does-.NET-JIT-a-method-and-Tiered-Compilation/ -->
     <TieredCompilation>true</TieredCompilation>
+    <TreatWarningsAsErrors Condition="'$(TreatWarningsAsErrors)' == 'true'">true</TreatWarningsAsErrors>
     <!--#if (!IIS)-->
     <!-- Disable publishing of a web.config file for IIS when calling dotnet publish. -->
     <!--#endif-->
diff --git a/Source/Content/GraphQLTemplate/.template.config/dotnetcli.host.json b/Source/Content/GraphQLTemplate/.template.config/dotnetcli.host.json
index ee9c3b29b..62e782cf0 100644
--- a/Source/Content/GraphQLTemplate/.template.config/dotnetcli.host.json
+++ b/Source/Content/GraphQLTemplate/.template.config/dotnetcli.host.json
@@ -19,6 +19,9 @@
     "AuthorXmlEncoded": {
       "isHidden": true
     },
+    "TreatWarningsAsErrors": {
+      "longName": "treat-warnings-as-errors"
+    },
     "Mutations": {
       "longName": "mutations"
     },
diff --git a/Source/Content/GraphQLTemplate/.template.config/template.json b/Source/Content/GraphQLTemplate/.template.config/template.json
index 6169ab300..8a5147359 100644
--- a/Source/Content/GraphQLTemplate/.template.config/template.json
+++ b/Source/Content/GraphQLTemplate/.template.config/template.json
@@ -132,6 +132,13 @@
       "valueSource": "Author",
       "valueTransform": "xmlEncode"
     },
+    // TreatWarningsAsErrors
+    "TreatWarningsAsErrors": {
+      "type": "parameter",
+      "datatype": "bool",
+      "defaultValue": "true",
+      "description": "Treat warnings as errors."
+    },
 
     // Mutations
     "Mutations": {
diff --git a/Source/Content/GraphQLTemplate/GraphQLTemplate.csproj b/Source/Content/GraphQLTemplate/GraphQLTemplate.csproj
index a18e83a67..7252645b1 100644
--- a/Source/Content/GraphQLTemplate/GraphQLTemplate.csproj
+++ b/Source/Content/GraphQLTemplate/GraphQLTemplate.csproj
@@ -1,8 +1,8 @@
-<Project Sdk="Microsoft.NET.Sdk.Web">
+<Project Sdk="Microsoft.NET.Sdk.Web">
   <!--#if (AuthoringMode)-->
   <PropertyGroup>
     <!-- Modify these constants to enable/disable a feature to debug the template. Note that this only affects the C#. -->
-    <DefineConstants>$(DefineConstants);Mutations;Subscriptions;Kestrel;IIS;NGINX;Azure;ApplicationInsights;HealthCheck;HttpsEverywhere;HstsPreload;ForwardedHeaders;HostFiltering;ResponseCaching;CORS;HumansTxt;RobotsTxt;CorrelationId;ResponseCompression</DefineConstants>
+    <DefineConstants>$(DefineConstants);TreatWarningsAsErrors;Mutations;Subscriptions;Kestrel;IIS;NGINX;Azure;ApplicationInsights;HealthCheck;HttpsEverywhere;HstsPreload;ForwardedHeaders;HostFiltering;ResponseCaching;CORS;HumansTxt;RobotsTxt;CorrelationId;ResponseCompression</DefineConstants>
     <!-- Workaround to build this project: https://github.com/dotnet/templating/issues/1438 -->
     <ApplicationInsights>true</ApplicationInsights>
     <Azure>true</Azure>
@@ -25,6 +25,7 @@
     <!-- Enable tiered JIT compilation for better performance.
          See http://mattwarren.org/2017/12/15/How-does-.NET-JIT-a-method-and-Tiered-Compilation/ -->
     <TieredCompilation>true</TieredCompilation>
+    <TreatWarningsAsErrors Condition="'$(TreatWarningsAsErrors)' == 'true'">true</TreatWarningsAsErrors>
     <!--#if (!IIS)-->
     <!-- Disable publishing of a web.config file for IIS when calling dotnet publish. -->
     <!--#endif-->