diff --git a/springdoc-openapi-common/src/main/java/org/springdoc/core/AbstractRequestService.java b/springdoc-openapi-common/src/main/java/org/springdoc/core/AbstractRequestService.java
index 87469e4ab..5df680f5a 100644
--- a/springdoc-openapi-common/src/main/java/org/springdoc/core/AbstractRequestService.java
+++ b/springdoc-openapi-common/src/main/java/org/springdoc/core/AbstractRequestService.java
@@ -334,7 +334,7 @@ else if (!RequestMethod.GET.equals(requestMethod)) {
 				Entry<String, Parameter> entry = it.next();
 				Parameter parameter = entry.getValue();
 				if (!ParameterIn.PATH.toString().equals(parameter.getIn())) {
-					io.swagger.v3.oas.models.media.Schema<?> itemSchema = new io.swagger.v3.oas.models.media.Schema<>() ;
+					io.swagger.v3.oas.models.media.Schema<?> itemSchema = new io.swagger.v3.oas.models.media.Schema<>();
 					itemSchema.setName(entry.getKey());
 					itemSchema.setDescription(parameter.getDescription());
 					itemSchema.setDeprecated(parameter.getDeprecated());
@@ -398,7 +398,10 @@ public static Collection<Parameter> getHeaders(MethodAttributes methodAttributes
 			Parameter parameter = new Parameter().in(ParameterIn.HEADER.toString()).name(entry.getKey()).schema(schema);
 			if (map.containsKey(entry.getKey())) {
 				parameter = map.get(entry.getKey());
-				if (StringUtils.isNotEmpty(entry.getValue()))
+				List existingEnum = null;
+				if (parameter.getSchema() != null && !CollectionUtils.isEmpty(parameter.getSchema().getEnum()))
+					existingEnum = parameter.getSchema().getEnum();
+				if (StringUtils.isNotEmpty(entry.getValue()) && (existingEnum==null || !existingEnum.contains(entry.getValue())))
 					parameter.getSchema().addEnumItemObject(entry.getValue());
 				parameter.setSchema(parameter.getSchema());
 			}
diff --git a/springdoc-openapi-webmvc-core/src/test/java/test/org/springdoc/api/v30/app47/BasicController.java b/springdoc-openapi-webmvc-core/src/test/java/test/org/springdoc/api/v30/app47/BasicController.java
new file mode 100644
index 000000000..0a509dbdd
--- /dev/null
+++ b/springdoc-openapi-webmvc-core/src/test/java/test/org/springdoc/api/v30/app47/BasicController.java
@@ -0,0 +1,26 @@
+package test.org.springdoc.api.v30.app47;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping(path = "/")
+public class BasicController {
+
+    @GetMapping(headers = {"foo=bar"})
+    public String get1() {
+        return null;
+    }
+
+    @GetMapping(headers = {"fi=ri"})
+    public String get2() {
+        return null;
+    }
+
+    @GetMapping(
+        headers = {"User-Agent=" + "MyUserAgent"})
+    public String get3() {
+        return null;
+    }
+}
diff --git a/springdoc-openapi-webmvc-core/src/test/resources/results/3.0.1/app47.json b/springdoc-openapi-webmvc-core/src/test/resources/results/3.0.1/app47.json
index 7239e937b..b683fac32 100644
--- a/springdoc-openapi-webmvc-core/src/test/resources/results/3.0.1/app47.json
+++ b/springdoc-openapi-webmvc-core/src/test/resources/results/3.0.1/app47.json
@@ -40,7 +40,60 @@
           }
         }
       }
+    },
+    "/": {
+      "get": {
+        "tags": [
+          "basic-controller"
+        ],
+        "operationId": "get1_1_1",
+        "parameters": [
+          {
+            "name": "foo",
+            "in": "header",
+            "schema": {
+              "type": "string",
+              "enum": [
+                "bar"
+              ]
+            }
+          },
+          {
+            "name": "fi",
+            "in": "header",
+            "schema": {
+              "type": "string",
+              "enum": [
+                "ri"
+              ]
+            }
+          },
+          {
+            "name": "User-Agent",
+            "in": "header",
+            "schema": {
+              "type": "string",
+              "enum": [
+                "MyUserAgent"
+              ]
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "*/*": {
+                "schema": {
+                  "type": "string"
+                }
+              }
+            }
+          }
+        }
+      }
     }
   },
   "components": {}
 }
+  
\ No newline at end of file