The amount of acquisitions has been increasing over the last decades and has been used as a growth strategy by firms all over the world. However, more than fifty percent of all acquisitions never deliver the initially expected value, which in many cases is due to poor integration management of the organizational culture in the post-acquisition phase. Where, in contrast, acquisitions which are integrated into the organizational culture of the acquirer, can see a decrease in social conflicts and receive a higher employee commitment. Which in turn can help the acquisition to provide and remain its human capital and value.  With the support of a Swedish business consulting firm, this study hopes to shed light upon how firms integrate organizational culture in the post-acquisition phase, and which integration management tools are used in the process. This study uses a single opportunistic case study combined with a qualitative and an inductive approach, to gather and handle the data. Where the empirical data was mainly collected through interviews. The results of this thesis show that integration of organizational culture in the post-acquisition phase, is mainly managed through supportive leadership and training, in the business consulting firm. Where those main management activities consist of several different integration management tools.