diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptAngularClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptAngularClientCodegen.java
index 0d681fdc030a..4ad14121fa5b 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptAngularClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptAngularClientCodegen.java
@@ -589,6 +589,15 @@ private boolean markHttpResource(CodegenOperation op, Set<String> nicknames) {
         return true;
     }
 
+    @Override
+    public Map<String, Object> postProcessSupportingFileData(Map<String, Object> objs) {
+        // supporting files bundle puts server URL over additionalProperties, keep user supplied basePath
+        if (additionalProperties.containsKey("basePath")) {
+            objs.put("basePath", additionalProperties.get("basePath"));
+        }
+        return super.postProcessSupportingFileData(objs);
+    }
+
     @Override
     public ModelsMap postProcessModels(ModelsMap objs) {
         ModelsMap result = super.postProcessModels(objs);
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/typescriptangular/TypeScriptAngularClientCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/typescriptangular/TypeScriptAngularClientCodegenTest.java
index dbece37188b2..64e0c3411a32 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/typescriptangular/TypeScriptAngularClientCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/typescriptangular/TypeScriptAngularClientCodegenTest.java
@@ -453,6 +453,22 @@ public void testBasePath() throws IOException {
         assertThat(fileContents).containsOnlyOnce("basePath = '/relative/url'");
     }
 
+    @Test
+    public void testBasePathFromAdditionalProperties() throws IOException {
+        for (String basePath : new String[]{"", "/api"}) {
+            File output = Files.createTempDirectory("angular-base-path").toFile();
+            output.deleteOnExit();
+            CodegenConfigurator configurator = new CodegenConfigurator()
+                    .setGeneratorName("typescript-angular")
+                    .setInputSpec("src/test/resources/3_0/typescript-angular/issue_20760.yaml")
+                    .setOutputDir(output.getAbsolutePath())
+                    .addAdditionalProperty("basePath", basePath);
+            new DefaultGenerator().opts(configurator.toClientOptInput()).generate();
+            String baseService = Files.readString(output.toPath().resolve("api.base.service.ts"));
+            assertThat(baseService).containsOnlyOnce("protected basePath = '" + basePath + "';");
+        }
+    }
+
     @Test
     public void testEnumAsConst() throws IOException {
         // GIVEN