Purpose: The purpose of this paper is to design and test an online team intervention for university students, focusing on communication, leadership and team processes, to influence team cohesion and subsequently team assignment performance. It was administered twice as a formative feedback measure and once as a summative evaluation measure across a semester. Design/methodology/approach: Survey data were collected from 154 university students across four management modules in a large Australian university. Multiple regression analysis was used to test the hypotheses and open-ended questions were used to understand why the team intervention was effective. Findings: The results showed that the implementation of an effective team intervention leads to higher levels of team cohesion and subsequently team performance. Open-ended responses revealed that the team intervention caused students to develop team-based sills and increase regular contributions. Practical implications: In order to develop positive team behaviours amongst students in group assignments and increase the effectiveness of team-based learning activities, educators should implement a regular and process focused team contribution intervention, like the one proposed in this study. Originality/value: This research contributes to the team intervention literature by drawing on the social information processing perspective, to demonstrate how an intervention that is based on the students' social processing, task focused, regular implementation and formative feedback has a salient effect over team cohesion.