The scarcity of IT resources and technological advancements in high-tech small and medium enterprises (SMEs) require leaders to embed IT ambidexterity - simultaneous pursuit of IT exploitation and IT exploration activities - into their organization's strategy, which could be challenging. To better understand how leaders enable IT ambidexterity, this study focuses on the leadership decision-making style (directive decision-making and participative decision-making) as a key driving factor. Moreover, we examine how and when leadership decision-making styles are most effective in enacting IT ambidexterity by considering new product development (NPD) team diversity and shared vision as two important contingencies. Finally, we test the role of IT ambidexterity in improving NPD performance. We analyse our research model using survey data from 292 high-tech SMEs. Our findings suggest that both decision-making styles enable IT ambidexterity, however, participative decision-making style is more effective in highly diverse NPD teams and directive decision-making style should be preferred when shared vision is a dominant factor among NPD team members. Our results also show that IT ambidexterity significantly enhances NPD performance. We discuss our contribution to information systems (IS) and ambidexterity research and provide implications for practice.