As start-ups reach a point where they must seek new markets or otherwise expand its business to find a sustainable operational level, they enter the scaling phase. As scaling poses several new or changed parameters as well as challenges for the venture, the question of how the leadership changes arises when scaling. This thesis will investigate how Swedish startups adapt their leadership when scaling up. This is a qualitative study based on multiple interviews, using thematic analysis. Scaling calls for adopting a transformational leadership approach, emphasizing on how to inspire and motivate team members, how to create a sense of inclusion with the team members and how to create effective collaboration and conflict solving in the team. Maintaining the company culture during scaling is key. Furthermore, by fostering empowered autonomous teams, keeping the organization flat and nimble, implementing lean functions for HR and finance, the leader ensures to make time for implementing the aforementioned themes. Finally, external stakeholders, Venture Capital, provides necessary funding and should also be used as a source of coaching or mentorship. However, there is a risk to be tied up to performance metrics that are sub-optimal for the scale-up. For future considerations and research, one should investigate how vision and strategy is implemented during the scaling and how is a lean and efficient communication across the scaling venture secured.