diff --git a/changelogs/fragments/1881-allow-s3_object-to-specify-content-type-in-metadata.yml b/changelogs/fragments/1881-allow-s3_object-to-specify-content-type-in-metadata.yml
new file mode 100644
index 00000000000..6051a344d5e
--- /dev/null
+++ b/changelogs/fragments/1881-allow-s3_object-to-specify-content-type-in-metadata.yml
@@ -0,0 +1,3 @@
+bugfixes:
+  - s3_object - when doing a put and specifying ``Content-Type`` in metadata, this module (since 6.0.0) erroneously set the ``Content-Type`` to ``None`` causing the put to fail.
+    Fix now correctly honours the specified ``Content-Type`` (https://github.com/ansible-collections/amazon.aws/issues/1881).
diff --git a/plugins/modules/s3_object.py b/plugins/modules/s3_object.py
index 8dd8275ffd7..0adb2e8bbaa 100644
--- a/plugins/modules/s3_object.py
+++ b/plugins/modules/s3_object.py
@@ -654,15 +654,14 @@ def path_check(path):
         return False
 
 
-def get_content_type(src, present=True):
-    if not present:
-        content_type = None
-        if src:
-            content_type = mimetypes.guess_type(src)[0]
-        if content_type is None:
-            # s3 default content type
-            content_type = "binary/octet-stream"
-        return content_type
+def guess_content_type(src):
+    if src:
+        content_type = mimetypes.guess_type(src)[0]
+        if content_type:
+            return content_type
+
+    # S3 default content type
+    return "binary/octet-stream"
 
 
 def get_extra_params(
@@ -747,7 +746,8 @@ def upload_s3file(
             elif isinstance(permissions, list):
                 extra["ACL"] = permissions[0]
 
-        extra["ContentType"] = get_content_type(src, present=extra.get("ContentType"))
+        if "ContentType" not in extra:
+            extra["ContentType"] = guess_content_type(src)
 
         if src:
             s3.upload_file(aws_retry=True, Filename=src, Bucket=bucket, Key=obj, ExtraArgs=extra)
diff --git a/tests/integration/targets/s3_object/tasks/main.yml b/tests/integration/targets/s3_object/tasks/main.yml
index cb7b89bd389..8cb9970ab70 100644
--- a/tests/integration/targets/s3_object/tasks/main.yml
+++ b/tests/integration/targets/s3_object/tasks/main.yml
@@ -458,6 +458,34 @@
           - "'Object deleted from bucket' in result.msg"
           - result is changed
 
+    - name: test putting an object in the bucket with metadata set
+      s3_object:
+        bucket: "{{ bucket_name }}"
+        mode: put
+        src: "{{ remote_tmp_dir }}/upload.txt"
+        metadata: "Content-Type=text/plain"
+        object: delete_meta.txt
+        tags:
+            "lowercase spaced": "hello cruel world"
+            "Title Case": "Hello Cruel World"
+      retries: 3
+      delay: 3
+      register: result
+
+    - assert:
+        that:
+          - result is changed
+          - result.msg == "PUT operation complete"
+
+    - name: test delobj to just delete an object in the bucket
+      s3_object:
+        bucket: "{{ bucket_name }}"
+        mode: delobj
+        object: delete_meta.txt
+      retries: 3
+      delay: 3
+      register: result
+
     - name: test putting an encrypted object in the bucket
       s3_object:
         bucket: "{{ bucket_name }}"