The principal aim of this study is to explore how the experience gained by self initiated expatriates (SIEs) during international assignments (IAs) impacts on the development of global leadership competencies (GLC). Although IAs are considered to be the most effective way to develop successful global leaders (Kohonen, 2005; Reichard et al., 2015; Ng et al., 2009; McCall., 2010), evidence is scarce on how these leaders actually develop during an IA (Bonache et al., 2001). The research study seeks to fill this void regarding SIEs’ learning and development of GLC while working abroad. The second aim of this study is to explore the GLC required by a SIE to be efficient within the context of the Gulf Cooperation Council (GCC) countries. This thesis develops a conceptual framework by blending three separate but interrelated theories, namely experiential learning (Kolb, 1984), sensemaking (Weick, 1995) and impression management (Goffman, 1959). This conceptual framework is used as a lens to inform the research question. The core research focus is ‘how does an international assignment impact on the development of global leadership competencies of SIEs?’ A qualitative research design was used in the form of 30 semi -structured interviews with top and middle level managers working in MNEs and local organisations within one of the GCC countries. Snowball sampling was used to generate the sample. Moreover, Flanagan’s (1954) critical incident technique (CIT) was chosen in order to frame the subjects narratives. Thematic analysis (TA) was used to analyse the data. The findings indicate that SIEs went through five stages of experiential learning to develop GLC and adjust cross-culturally. Moreover, it was clear from the findings that SIEs from developed countries encountered more serious challenges in comparison with SIEs from developing countries. Such discrepancies are potentially due to the lack of cultural overlap between Western SIEs’ individualist cultural backgrounds and the collectivist cultures in GCC countries. Based on the research findings, the main theoretical contribution of this thesis is the development of a framework for enhancing SIEs’ learning and development of GLC, and achieving cross cultural adjustment, coupled with the empirical study.