diff --git a/docs/generators/csharp-netcore.md b/docs/generators/csharp-netcore.md
index c7935752d018..840bcba517ee 100644
--- a/docs/generators/csharp-netcore.md
+++ b/docs/generators/csharp-netcore.md
@@ -17,6 +17,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |modelPropertyNaming|Naming convention for the property: 'camelCase', 'PascalCase', 'snake_case' and 'original', which keeps the original name| |PascalCase|
 |netCoreProjectFile|Use the new format (.NET Core) for .NET project files (.csproj).| |false|
 |nonPublicApi|Generates code with reduced access modifiers; allows embedding elsewhere without exposing non-public API calls to consumers.| |false|
+|nullableReferenceTypes|Set the nullable reference types property to true or false. Default is false.| |false|
 |optionalAssemblyInfo|Generate AssemblyInfo.cs.| |true|
 |optionalEmitDefaultValues|Set DataMember's EmitDefaultValue.| |false|
 |optionalMethodArgument|C# Optional method argument, e.g. void square(int x=10) (.net 4.0+ only).| |true|
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConstants.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConstants.java
index 2e7151dc94e2..4fb0299b5c56 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConstants.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConstants.java
@@ -208,6 +208,9 @@ public class CodegenConstants {
     public static final String DOTNET_FRAMEWORK = "targetFramework";
     public static final String DOTNET_FRAMEWORK_DESC = "The target .NET framework version.";
 
+    public static final String NULLABLE_REFERENCE_TYPES = "nullableReferenceTypes";
+    public static final String NULLABLE_REFERENCE_TYPES_DESC = "Set the nullable reference types property to true or false. Default is false.";
+
     public static final String TEMPLATING_ENGINE = "templatingEngine";
     public static final String TEMPLATING_ENGINE_DESC = "The templating engine plugin to use: \"mustache\" (default) or \"handlebars\" (beta)";
 
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
index eb263b34c378..2a53710a124e 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
@@ -47,6 +47,7 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
     protected boolean useCollection = false;
     protected boolean returnICollection = false;
     protected boolean netCoreProjectFileFlag = false;
+    protected boolean nullReferenceTypesFlag = false;
 
     protected String modelPropertyNaming = CodegenConstants.MODEL_PROPERTY_NAMING_TYPE.PascalCase.name();
 
@@ -356,6 +357,12 @@ public void processOpts() {
             additionalProperties.put(CodegenConstants.NETCORE_PROJECT_FILE, netCoreProjectFileFlag);
         }
 
+        if (additionalProperties.containsKey(CodegenConstants.NULLABLE_REFERENCE_TYPES)) {
+            setNullableReferenceTypes(convertPropertyToBooleanAndWriteBack(CodegenConstants.NULLABLE_REFERENCE_TYPES));
+        } else {
+            additionalProperties.put(CodegenConstants.NULLABLE_REFERENCE_TYPES, nullReferenceTypesFlag);
+        }
+
         if (additionalProperties.containsKey(CodegenConstants.INTERFACE_PREFIX)) {
             String useInterfacePrefix = additionalProperties.get(CodegenConstants.INTERFACE_PREFIX).toString();
             if ("false".equals(useInterfacePrefix.toLowerCase(Locale.ROOT))) {
@@ -1115,6 +1122,13 @@ public void setInterfacePrefix(final String interfacePrefix) {
         this.interfacePrefix = interfacePrefix;
     }
 
+    public void setNullableReferenceTypes(final Boolean nullReferenceTypesFlag){
+        this.nullReferenceTypesFlag = nullReferenceTypesFlag;
+        if (nullReferenceTypesFlag == true){
+            this.nullableType.add("string");
+        }
+    }
+
     public void setEnumNameSuffix(final String enumNameSuffix) {
         this.enumNameSuffix = enumNameSuffix;
     }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpNetCoreClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpNetCoreClientCodegen.java
index ff90d1e30e26..4167e054e2d1 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpNetCoreClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpNetCoreClientCodegen.java
@@ -230,6 +230,10 @@ public CSharpNetCoreClientCodegen() {
         cliOptions.add(modelPropertyNaming.defaultValue("PascalCase"));
 
         // CLI Switches
+        addSwitch(CodegenConstants.NULLABLE_REFERENCE_TYPES,
+            CodegenConstants.NULLABLE_REFERENCE_TYPES_DESC,
+            this.nullReferenceTypesFlag);
+
         addSwitch(CodegenConstants.HIDE_GENERATION_TIMESTAMP,
                 CodegenConstants.HIDE_GENERATION_TIMESTAMP_DESC,
                 this.hideGenerationTimestamp);
@@ -557,7 +561,7 @@ public void processOpts() {
 
         if (additionalProperties.containsKey(CodegenConstants.DISALLOW_ADDITIONAL_PROPERTIES_IF_NOT_PRESENT)) {
             this.setDisallowAdditionalPropertiesIfNotPresent(Boolean.parseBoolean(additionalProperties
-                    .get(CodegenConstants.DISALLOW_ADDITIONAL_PROPERTIES_IF_NOT_PRESENT).toString()));
+                .get(CodegenConstants.DISALLOW_ADDITIONAL_PROPERTIES_IF_NOT_PRESENT).toString()));
         }
 
         if (additionalProperties.containsKey(CodegenConstants.OPTIONAL_EMIT_DEFAULT_VALUES)) {