Extant literature has focussed on describing and explaining the internationalisation of firms, including SMEs, in terms of universal theories of internationalisation. In contrast, in the context of SMEs, there is an argument that internationalisation processes are unique and therefore no ‘one theory fits all’ SMEs. Informed by prior research on the factors that influence internationalisation in SMEs, and responding to calls for more indepth explanations of the internationalisation process and for explanations that adopt a multilevel perspective (environment, firm and entrepreneur) this study explores the internationalisation process of SMEs. The context for the study is the internationalisation of SMEs in the Irish Life Sciences sector. To understand the context that shapes the internationalisation processes of specific SMEs, the empirical research starts with a case study of the Irish Life Sciences Sector. This involves the identification of the population of firms in the Irish Life Sciences Sector (the creation of a database of Irish owned firms and a separate database of MNEs), and interviews with twelve industry experts. To understand the internationalisation processes of SMEs, the research focussed on five SMEs. These case studies are based on twenty-three interviews in total, involving the owners/entrepreneurs, senior managers, and development consultants from Enterprise Ireland. The thirty-five interviews occurred during the period January 2010 to March 2011. Analysis of the case studies and the industry level data suggests a conceptual framework that explains the internationalisation of SMEs in the Life Sciences industry in Ireland. Central to the framework is the application of a multilevel view, incorporating the firms’ environment, the firm, and the entrepreneur. The research presents an analysis of how three themes: on-going networking, trust building and learning, help to explain the internationalisation process of firms in the sector. Factors such as the entrepreneur, the firm’s team interactions and characteristics, and the firm’s environment help to drive the internationalisation process. This research makes a number of contributions. First, the research suggests a multilevel conceptual framework that describes the internationalisation process in the context of SMEs in the Irish Life Sciences sector. Second, the research suggests that a multilevel perspective of the internationalisation process offers a more complete explanation of the internationalisation process. Third, the research extends existing studies of the internationalisation of SMEs to a new context, the Irish Life Sciences sector.