This study highlighted the importance of software process tailoring (SPT) in modern software projects characterized by dynamic and evolutionary development. SPT is a collaborative practice, and the existing literature has focused on team-based knowledge aspects in performing SPT, whereas the quality of team interactions has rarely been discussed to address its conflictual nature. This study examined the teamwork quality (TWQ) framework with two team behavioral factors, namely team reflexivity and member autonomy, and developed a research model to explore how TWQ fits in the SPT’s conflicting context and how autonomy and reflexivity affect TWQ to promote SPT. The results showed that TWQ is essential for dealing with challenging tasks in SPT. The results also supported the evidence that reflexivity positively affects TWQ while member autonomy harms TWQ. When examining the mediating effect to see how TWQ operationalizes as an intermediate in the relationship between the two factors and SPT performance, this study found that reflexivity directly and indirectly boosts SPT performance. Member autonomy and SPT performance are independent when TWQ is the mediator. However, without TWQ, member autonomy negatively impacts SPT effectiveness and efficiency.