This master thesis was composed by the initiative of the authors following the discovery of a knowledge gap regarding the impact which supply chain power and supplier integration might have on focal companies’ efforts for sustainable supplier development of strategic critical suppliers. In a multiple case study with semi-structured interviews the authors gathered comparable empirical data from three large Swedish companies which were analysed through recognized theoretical frameworks. Findings indicated that supply chain power has an impact on focal companies’ ability to implement sustainable supplier development of strategic critical suppliers, while there were no clear signs of any impact which supplier integration might have on sustainable supplier development of strategic critical suppliers.