One of the most important variables to consider in physical education (PE) is motivation. The self-determination theory (SDT) represents an essential theoretical perspective to examine and understand adolescents' learning and motivation in PE. Based on this theory, the Situational Motivational Scale (SIMS) measures students' situational motivation related to a subject like PE. The aim of the present study is to examine the dimensionality, reliability, and construct validity of the Norwegian version of the SIMS among adolescents in PE. In total, 318 students from six schools completed the SIMS in their PE classes during the spring of 2016. Explorative and confirmatory factor analyses were conducted, suggesting the fourteen-item version of the SIMS to be superior to the sixteen-item version. The SIMS measurement model of adolescents' situational motivation in PE showed satisfactory reliability and construct validity.