ObjectiveTo develop and test an Objective Structured Assessment of Technical Skills (OSATS) score for the internal version and total breech extraction of the second twin if in a non‐engaged cephalic position.Materials and MethodsThis prospective interventional study took place in a tertiary obstetrics department in France. An objective scoring system was developed, and a standardized simulation scenario was set up. Score evaluation was blinded and analyzed according to group and number of past successful vaginal twin deliveries in real life. A satisfaction evaluation was performed, based on the “Student Design Scale” questionnaire.ResultsSimulation was performed on 33 participants in three groups: novice group (15 first‐ and second‐year residents), intermediate group (11 third‐ to sixth‐year residents), and expert group (seven senior obstetricians). The total score obtained by experts was higher than that of the intermediate group (P = 0.001), which was higher than that of the novice group (P < 0.001). In the intermediate group, no correlation was found between OSATS score and number of past successful vaginal twin deliveries. Participants' satisfaction was excellent.ConclusionThe OSATS score developed was reliable and valid to evaluate an internal version and a total breech extraction of the second twin, and to differentiate novice, intermediate, and expert practitioners.