One of the main goals for physical education is to develop the students' moral and ethical domain, where sportsmanship promotion is considered a key curricular component to tackle the achievement of this goal. This research aims to examine the influence of sport education on sportsmanship orientations in high school students. The participants were 148 (52.70% female; = 17.04, = 0.99) high school students who were randomized into an experimental group ( = 74), which received 16 basketball lessons under sport education conditions, and a control group ( = 74), which received 16 basketball lessons following a traditional teaching approach. Pre-intervention and post-intervention measures on sportsmanship orientations were collected in both groups. A 2 (time: pre-test and post-test) x 2 (group: Sport Education and Traditional Teaching) multivariate analysis of variance test was performed on the five sportsmanship orientations. The results showed, for time x group interactions, the absence of significant multivariate effects in the level of the five sportsmanship orientations among both groups at pre-test (Pillai's trace = 0.06, = 0.145). At post-test, significant multivariate effects were found in the level of each sportsmanship orientation between both groups in favor of the Sport Education group (Pillai's trace = 0.38, < 0.001). Furthermore, regarding within-group pre-test to post-test differences, while there were nonsignificant multivariate effects (Pillai's trace = 0.03, = 0.469) for the Traditional Teaching group; significant multivariate effects (Pillai's trace = 0.43, < 0.001) were found for the Sport Education group, showing an increase in the level of respect for social conventions, respect for rules and referees, and full commitment and respect for opponents. There were also nonsignificant effects across gender (inter-group analysis: Pillai's trace = 0.08, = 0.068; time x gender interaction: Pillai's trace = 0.03, = 0.497) and after-school sports (inter-group analysis: Pillai's trace = 0.02, = 0.776; time x after-school interaction: Pillai's trace = 0.01, = 0.981). In conclusion, sport education is an effective pedagogical model to be taken into consideration by physical education teachers in order to optimally promote the high school student's moral and ethical education via the development of sportsmanship orientations in the context of school physical education.