The aim of this study was to develop pre-service science teachers’ self-determined motivation toward environment before, after and five months following the environmental course activities guided by self-determination theory. The sample of the study was 33 pre-service science teachers who participated in an environmental science course. This course included various environmental problems guided by selfdetermination theory, group discussions and class discussions. Data were gathered by administration of motivation toward environment and amotivation toward environment scaling to pre-service science teachers. The results of the study illustrated that pre-service science teachers’ intrinsic motivation increased after the course activities and five months following the course. PSTs’ negative capacity beliefs which refer to lack of capacity beliefs causing amotivation toward environment declined after the course activities and in the follow-up measurement. Significant results could not be found regarding other subscales of motivation toward environment and amotivation toward environment scales. These findings suggest that pre-service science teachers’ self-determined motivation toward environment was developed throughout the environmental activities guided by self-determination theory. However, there is a need to study with the larger sample and make a longlasting research to be able to find more significant results.