diff --git a/lib/s3_helper.rb b/lib/s3_helper.rb
index 6c6ea76f87a..111c8b5ce19 100644
--- a/lib/s3_helper.rb
+++ b/lib/s3_helper.rb
@@ -111,37 +111,39 @@ class S3Helper
     end
 
     destination = get_path_for_s3_upload(destination)
-    if !Rails.configuration.multisite
-      options[:copy_source] = File.join(@s3_bucket_name, source)
+    source_object = if !Rails.configuration.multisite || source.include?(multisite_upload_path) || source.include?(@tombstone_prefix)
+      s3_bucket.object(source)
+    elsif @s3_bucket_folder_path
+      folder, filename = source.split("/", 2)
+      s3_bucket.object(File.join(folder, multisite_upload_path, filename))
     else
-      if source.include?(multisite_upload_path) || source.include?(@tombstone_prefix)
-        options[:copy_source] = File.join(@s3_bucket_name, source)
-      elsif @s3_bucket_folder_path
-        folder, filename = begin
-                             source.split("/", 2)
-                           end
-        options[:copy_source] = File.join(@s3_bucket_name, folder, multisite_upload_path, filename)
-      else
-        options[:copy_source] = File.join(@s3_bucket_name, multisite_upload_path, source)
-      end
+      s3_bucket.object(File.join(multisite_upload_path, source))
+    end
+
+    if source_object.size > FIFTEEN_MEGABYTES
+      options[:multipart_copy] = true
+      options[:content_length] = source_object.size
     end
 
     destination_object = s3_bucket.object(destination)
 
-    # TODO: copy_source is a legacy option here and may become unsupported
-    # in later versions, we should change to use Aws::S3::Client#copy_object
-    # at some point.
-    #
-    # See https://github.com/aws/aws-sdk-ruby/blob/version-3/gems/aws-sdk-s3/lib/aws-sdk-s3/customizations/object.rb#L67-L74
-    #
-    # ----
-    #
-    # Also note, any options for metadata (e.g. content_disposition, content_type)
-    # will not be applied unless the metadata_directive = "REPLACE" option is passed
-    # in. If this is not passed in, the source object's metadata will be used.
-    response = destination_object.copy_from(options)
+    # Note for small files that do not use multipart copy: Any options for metadata
+    # (e.g. content_disposition, content_type) will not be applied unless the
+    # metadata_directive = "REPLACE" option is passed in. If this is not passed in,
+    # the source object's metadata will be used.
+    # For larger files it copies the metadata from the source file and merges it
+    # with values from the copy call.
+    response = destination_object.copy_from(source_object, options)
 
-    [destination, response.copy_object_result.etag.gsub('"', '')]
+    etag = if response.respond_to?(:copy_object_result)
+      # small files, regular copy
+      response.copy_object_result.etag
+    else
+      # larger files, multipart copy
+      response.data.etag
+    end
+
+    [destination, etag.gsub('"', '')]
   end
 
   # Several places in the application need certain CORS rules to exist
diff --git a/spec/lib/s3_helper_spec.rb b/spec/lib/s3_helper_spec.rb
index f225c3bda09..f7beacf590e 100644
--- a/spec/lib/s3_helper_spec.rb
+++ b/spec/lib/s3_helper_spec.rb
@@ -100,26 +100,55 @@ describe "S3Helper" do
     let(:destination_key) { "original/1X/destination.jpg" }
     let(:s3_helper) { S3Helper.new("test-bucket", "", client: client) }
 
-    it "can copy an object from the source to the destination" do
+    it "can copy a small object from the source to the destination" do
+      source_stub = Aws::S3::Object.new(bucket_name: "test-bucket", key: source_key, client: client)
+      source_stub.stubs(:size).returns(5 * 1024 * 1024)
+      s3_helper.send(:s3_bucket).expects(:object).with(source_key).returns(source_stub)
+
       destination_stub = Aws::S3::Object.new(bucket_name: "test-bucket", key: destination_key, client: client)
       s3_helper.send(:s3_bucket).expects(:object).with(destination_key).returns(destination_stub)
-      destination_stub.expects(:copy_from).with(copy_source: "test-bucket/#{source_key}").returns(
-        stub(copy_object_result: stub(etag: "\"etag\""))
+
+      destination_stub.expects(:copy_from).with(source_stub, {}).returns(
+        stub(copy_object_result: stub(etag: '"etag"'))
       )
+
+      response = s3_helper.copy(source_key, destination_key)
+      expect(response.first).to eq(destination_key)
+      expect(response.second).to eq("etag")
+    end
+
+    it "can copy a large object from the source to the destination" do
+      source_stub = Aws::S3::Object.new(bucket_name: "test-bucket", key: source_key, client: client)
+      source_stub.stubs(:size).returns(20 * 1024 * 1024)
+      s3_helper.send(:s3_bucket).expects(:object).with(source_key).returns(source_stub)
+
+      destination_stub = Aws::S3::Object.new(bucket_name: "test-bucket", key: destination_key, client: client)
+      s3_helper.send(:s3_bucket).expects(:object).with(destination_key).returns(destination_stub)
+
+      options = { multipart_copy: true, content_length: source_stub.size }
+      destination_stub.expects(:copy_from).with(source_stub, options).returns(
+        stub(data: stub(etag: '"etag"'))
+      )
+
       response = s3_helper.copy(source_key, destination_key)
       expect(response.first).to eq(destination_key)
       expect(response.second).to eq("etag")
     end
 
     it "puts the metadata from options onto the destination if apply_metadata_to_destination" do
-      content_disposition = "attachment; filename=\"source.jpg\"; filename*=UTF-8''source.jpg"
+      source_stub = Aws::S3::Object.new(bucket_name: "test-bucket", key: source_key, client: client)
+      source_stub.stubs(:size).returns(5 * 1024 * 1024)
+      s3_helper.send(:s3_bucket).expects(:object).with(source_key).returns(source_stub)
+
       destination_stub = Aws::S3::Object.new(bucket_name: "test-bucket", key: destination_key, client: client)
       s3_helper.send(:s3_bucket).expects(:object).with(destination_key).returns(destination_stub)
-      destination_stub.expects(:copy_from).with(
-        copy_source: "test-bucket/#{source_key}", content_disposition: content_disposition, metadata_directive: "REPLACE"
-      ).returns(
-        stub(copy_object_result: stub(etag: "\"etag\""))
+
+      content_disposition = "attachment; filename=\"source.jpg\"; filename*=UTF-8''source.jpg"
+      options = { content_disposition: content_disposition, metadata_directive: "REPLACE" }
+      destination_stub.expects(:copy_from).with(source_stub, options).returns(
+        stub(data: stub(etag: '"etag"'))
       )
+
       response = s3_helper.copy(
         source_key, destination_key,
         options: { apply_metadata_to_destination: true, content_disposition: content_disposition }