Despite the increasing use of simulation games in business education, only few studies have explored the cognitive processes that learners employ while playing the game, with quite controversial results about the students’ learning outcomes. The current study analyses the impact of a Business Simulation Game (BSG) on the cognitive processes related to the “Structure of the Observed Learning Outcome” (SOLO) taxonomy. Moreover, overall learning performance and perceived teamwork competency have been investigated. A quasi-experimental pre and post-test design was applied. Eighty (80) university students played a marketing simulation game to practise a business marketing plan. The results showed a significant improvement in the unistructural and extended abstract levels of the taxonomy after playing the game. There was no significant difference in the multi-structural level while the effect on the relational level was negative. Also, a strong, positive correlation between perceived teamwork competency and learning performance was found. Implications for instructional designers and educators are discussed.