diff --git a/mongo/options/collectionoptions.go b/mongo/options/collectionoptions.go
index 04fda6d779..7904dbd672 100644
--- a/mongo/options/collectionoptions.go
+++ b/mongo/options/collectionoptions.go
@@ -95,6 +95,9 @@ func MergeCollectionOptions(opts ...*CollectionOptions) *CollectionOptions {
 		if opt.Registry != nil {
 			c.Registry = opt.Registry
 		}
+		if opt.BSONOptions != nil {
+			c.BSONOptions = opt.BSONOptions
+		}
 	}
 
 	return c
diff --git a/mongo/options/dboptions.go b/mongo/options/dboptions.go
index 8a380d2168..38ee13550b 100644
--- a/mongo/options/dboptions.go
+++ b/mongo/options/dboptions.go
@@ -95,6 +95,9 @@ func MergeDatabaseOptions(opts ...*DatabaseOptions) *DatabaseOptions {
 		if opt.Registry != nil {
 			d.Registry = opt.Registry
 		}
+		if opt.BSONOptions != nil {
+			d.BSONOptions = opt.BSONOptions
+		}
 	}
 
 	return d