diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/templating/mustache/IndentedLambda.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/templating/mustache/IndentedLambda.java
index 72a6cbb4251..d6dceb581be 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/templating/mustache/IndentedLambda.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/templating/mustache/IndentedLambda.java
@@ -109,7 +109,8 @@ public class IndentedLambda implements Mustache.Lambda {
 
         String prefixedIndention = StringUtils.repeat(new String(Character.toChars(spaceCode)), prefixSpaceCount);
         StringBuilder sb = new StringBuilder();
-        String[] lines = text.split(System.lineSeparator());
+        // use \n instead of System.lineSeparator (e.g. \r\n in Windows) as templates use \n
+        String[] lines = text.split("\n");
         for (int i = 0; i < lines.length; i++) {
             String line = lines[i];
             // Mustache will apply correct indentation to the first line of a template (to match declaration location).
@@ -121,9 +122,9 @@ public class IndentedLambda implements Mustache.Lambda {
 
             sb.append(line);
 
-            // We've split on the system's line separator. We don't want to add an additional trailing line.
+            // We've split on \n. We don't want to add an additional trailing line.
             if (i < lines.length - 1) {
-                sb.append(System.lineSeparator());
+                sb.append("\n");
             }
         }
         writer.write(sb.toString());
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/templating/mustache/IndentedLambdaTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/templating/mustache/IndentedLambdaTest.java
index ef46b2767e7..223afaf913f 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/templating/mustache/IndentedLambdaTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/templating/mustache/IndentedLambdaTest.java
@@ -6,18 +6,17 @@ import org.testng.annotations.Test;
 
 public class IndentedLambdaTest extends LambdaTest {
 
-    String lineSeparator = System.lineSeparator();
+    String lineSeparator = "\n";
 
     @Test
     public void defaultIndentTest() {
         // Given
         Map<String, Object> ctx = context("indented", new IndentedLambda());
-        String lineSeparator = System.lineSeparator();
 
         // When & Then
         // IndentedLambda applies indentation from second line on of a template.
         test("first line" + lineSeparator + "    second line",
-                "{{#indented}}first line" + lineSeparator +"second line{{/indented}}", ctx);
+                "{{#indented}}first line" + lineSeparator + "second line{{/indented}}", ctx);
     }
 
     @Test
@@ -28,7 +27,7 @@ public class IndentedLambdaTest extends LambdaTest {
         // When & Then
         // IndentedLambda applies indentation from second line on of a template.
         test("first line" + lineSeparator + "        second line",
-                "{{#indented}}first line" + lineSeparator +"second line{{/indented}}", ctx);
+                "{{#indented}}first line" + lineSeparator + "second line{{/indented}}", ctx);
     }