The pilot and the flight instructor were performing flight training in the turbo-propeller-powered, multi-engine airplane. After completing two uneventful takeoffs and landings, the instructor and the pilot briefed that they would next perform a no-flap landing. While on the downwind leg of the traffic pattern, the pilot called for the before landing checklist. The instructor began reading the checklist, the pilot pushed the propeller controls fully forward, and the flight instructor mentioned that the pilot needed to hold the airplane’s attitude in order to slow the airplane to the desired airspeed. The flight instructor further described, “I was coaching the [pilot] on centerline and speed and neither of us realized that we had not completed the landing checklist.” During the landing flare, the flight instructor heard a metallic scraping sound, and began to abort the landing, about which time the pilot noted that the landing gear was not extended. After two attempts to increase engine power and climb, the flight instructor realized that the airplane was not controllable and decided to land on the grass next to the runway with the landing gear retracted. The airplane’s right wing was substantially damaged during the landing. The operator reported that there were no preimpact mechanical malfunctions or failures of the airplane that would have precluded normal operation, nor did either of the flight crew report any, with the exception that neither crewmember recalled hearing the landing gear position warning system horn activate at any point. Maintenance personnel tested the system following the accident and noted no anomalies.