The Bloch MB-155 would have replaced the MB-151 and MB-152 in French service if France had remained in the war longer. It used the same Gnome & Rhône 14N-49 engine as the later MB-152s. It had an improved engine cowling, and more fuel capacity. In order to make room for the new fuel tanks, the cockpit was moved back. Firepower was increased by the addition of two extra 7.5mm machine guns, while the two cannon were changed to a belt-fed model. The wings and undercarriage remained identical to those used in the MB-152, which greatly sped up the change in production.
The new aircraft was marked improvement on the MB-152. It was slightly faster, with a top speed of 323 mph at 18,000 feet, better armed and with a longer range. The first prototype flew in December 1939, the first production machine on 3 April 1940. By May 1940 the MB-155 had entered full production, but only nine had been completed by the time of the armistice of 25 June.
The MB-155 factory was initially occupied by the Germans, but once the armistice came into effect it became part of the unoccupied zone. The nine MB-155s already completed were joined by nineteen that had been near completion, and equipped the 1st Escadrille of G.C. I/8 in the Armistice Air Force. After the German invasion of unoccupied France in November 1942 the surviving MB-155s were seized by the Luftwaffe.