Qualstar Corporation is an American manufacturer of magnetic tape data storage products, based in Simi Valley, California.

A number of models supporting AIT, SAIT, SDLT and LTO tape drive technologies were produced.

In 2010 Qualstar introduced the RLS-8500 Series that house up to 114 tapes and five LTO drives in a 10U high mechanism.

Using patented technology, the XLS-Series introduced interchangeable Library Resource Modules (LRMs)and storage modules (MEMs) in highly flexible configurations that could be combined to exceed 7,000 tapes and 128 LTO tape drives.

The XLS family has continued to expand, adding four more LRM models and a second MEM module.