diff --git a/glance_store/_drivers/s3.py b/glance_store/_drivers/s3.py
index 95d4c84b..49a17eb0 100644
--- a/glance_store/_drivers/s3.py
+++ b/glance_store/_drivers/s3.py
@@ -180,6 +180,7 @@ Related Options:
 """),
     cfg.IntOpt('s3_store_large_object_size',
                default=DEFAULT_LARGE_OBJECT_SIZE,
+               min=0,
                help="""
 What size, in MB, should S3 start chunking image files and do a multipart
 upload in S3.
@@ -190,7 +191,7 @@ upload the image to S3 as is or to split it (Multipart Upload).
 Note: You can only split up to 10,000 images.
 
 Possible values:
-    * Any positive integer value
+    * Any positive integer value or zero
 
 Related Options:
     * s3_store_large_object_chunk_size
@@ -473,6 +474,8 @@ class Store(glance_store.driver.Store):
         if not result:
             if param == 's3_store_create_bucket_on_put':
                 return result
+            if param == 's3_store_large_object_size':
+                return result
             if param == 's3_store_region_name':
                 return result
             if param == 's3_store_cacert':
diff --git a/releasenotes/notes/s3-store-large-object-size-zero-a24229ae6955b799.yaml b/releasenotes/notes/s3-store-large-object-size-zero-a24229ae6955b799.yaml
new file mode 100644
index 00000000..b5474add
--- /dev/null
+++ b/releasenotes/notes/s3-store-large-object-size-zero-a24229ae6955b799.yaml
@@ -0,0 +1,10 @@
+---
+features:
+  - |
+    Support setting ``s3_store_large_object_size`` to ``0`` to force multipart
+    upload when ``image_size`` is unknown.
+fixes:
+  - |
+    `Bug #2043740 <https://bugs.launchpad.net/glance-store/+bug/2043740>`_:
+    ``s3_store_large_object_size`` can be set to ``0`` to force multipart
+    upload when creating an image in the S3 backend from a Cinder volume.