Recent efforts have been made to operationalise the performance of born-global (BG) firms in ways that acknowledge their unique characteristics and strategies. This paper explores the BG development process and assesses the relevance of various types of performance measures. Two questions are addressed: first, which types of performance measures are most relevant to BGs in the various phases of their development? Second, how do initial market selection and internationalisation speed influence BG development, and therefore the relevance of performance measures? Drawing on international entrepreneurship theory, this study undertook a progressive focussing, theory development/refinement (abduction) approach. Utilising a multiple case study design, data were collected primarily through in-depth, face-to-face interviews with senior managers from Australian BGs and with industry experts and analysed using open, axial and selective coding. Data were collected from BGs across each of the three phases of BG development: pre-start-up/venture creation; early international entry/development; and international growth/consolidation. Building on recent conceptualisations of the BG development process, we found that the relevance of performance measures is dependent, in part, on the BG s phase of development. Further, the rapidity of internationalisation and the psychic distance of initial markets influence the duration of each phase. The unique characteristics and strategies of BGs should be reflected in the measures used to evaluate their performance in each of the three phases. This study represents the first empirical examination into the measurement of BG performance across the phases of development, providing a foundation for future scale development.