Purpose: The purpose of this paper is to chart the growth of Millicom, a Luxembourg based but international operator of cable and mobile telecommunication networks. Design/methodology/approach: A longitudinal case study approach is adopted covering the period 1990–2019 (inclusive). Data are drawn from multiple sources, including annual reports of Millicom and the trade press. Findings: The analysis of this study highlights the changing geographical focus of Millicom. When founded, it was present in three regions – Africa, Asia and Latin America – but over time, it has concentrated its operations on the latter region. Secondly, Millicom has widened its operational remit to include more lines of business. This reflects the converged strategy that has been adopted in Latin America, where it is now active in cable and mobile telecommunication markets. Research limitations/implications: The paper illustrates the difficulties of research into privately owned companies and especially those active in the telecommunications industry in the early 1990s. Practical implications: The analysis of this study highlights the challenges of researching companies active, as the telecommunications sector began to be liberalised. There is limited data in the public domain covering the early 1990s, not least because the Internet as understood today had not yet emerged. Originality/value: To the best of authors’ knowledge, this is the first academic paper to analyse the internationalisation of Millicom.