The Bombardier BRJX, or Bombardier Regional Jet eXpansion, was a project for a larger regional jet than the Canadair Regional Jet. Instead of 2+3 seating, the BRJX was to have a wider fuselage with 3+3 seating, and underwing engine pods. It was projected to seat 80 to 120 passengers, abutting the smallest narrow-body jetliners of the large commercial passenger jets (A318, B717). The project was shelved by Bombardier. Bombardier's competitor, Embraer, continued their equivalent project, and produced the EMBRAER E-Jets series of 70 to 100 seaters. The project was shelved in favour of streching the CRJ-700 into the CRJ-900.

The BRJX program has since been replaced by the Bombardier CSeries project.