The Bombardier CSeries (also C Series) is a family of narrow-body, twin-engine, medium-range jet airliners by Canadian manufacturer Bombardier Aerospace. The CSeries models are the 110-seat CS100 and the 135-seat CS300. These models were initially named C110 and C130, respectively. In certification documentation, the CSeries family is designated Bombardier BD-500, with suffix -1A10 for the CS100 and-1A11 for the CS300.

The CS100 model of the CSeries took its maiden flight on 16 September 2013 and was awarded an initial type certification by Transport Canada on 18 December 2015. It entered service on 15 July 2016 with Swiss Global Air Lines. The CS100 is to compete with the Embraer E195-E2.

The CS300 first flew on 27 February 2015 and received an initial type certification on 11 July 2016. It is forecast to enter service in the fourth quarter of 2016 with air Baltic. The model is to compete with the Boeing737 MAX 7, Airbus A319neo, and Irkut MC-21-200.