Despite being ubiquitously used, the concept of alignment remains inchoate. Existing literature offers more than 30 interpretations of the term and very few attempts to develop an objective indicators-based metric of alignment. This state of the field makes assessments of the degree to which states are aligned problematic. This article systematises the theoretical knowledge about alliances, alignments, strategic partnerships, and other forms of cooperation and draws on some empirical observations to develop a ‘stadial model of alignment formation’ (SMAF). The model conceptualises, operationalises, measures, and explains interstate alignment with greater precision and consistency. It also includes the explanatory factors in the form of the three balances – the balance of power, the balance of threat, and the balance of interest – and connections between them located along the stages of alignment formation. As such, the SMAF framework gauges the relative scale and depth of strategic alignments and can facilitate comparative analysis.