<p>This study investigates how social complexity emerged on the Andean Altiplano of South America during the Terminal Archaic (5300–3500 cal BP) and Early Formative periods (3500–3000/2800 cal BP). Instead of viewing this transformation as a single, uniform process, we unpack it into multiple dimensions, assessing the accumulated empirical evidence and exploring its links to sedentism, food production, the rise of institutions such as exchange networks, religious practices, leadership, and the potential for social inequalities. Evidence suggests that sedentism in the Terminal Archaic Period was gradual and frequently incomplete, characterized primarily by semi-sedentary behavior linked to the repeated reoccupation of sites, pastoral mobility, and the social importance of burial grounds. More permanent occupation was achieved in the northern Altiplano during the Early Formative Period, while semi-nomadic lifestyles persisted in the south. Dietary and technological data challenge models that link social complexity to demographic pressure and intensive agriculture. Subsistence remained traditional, based on Archaic dietary patterns, along with the gradual adoption of cultivation and technologies such as pottery and archery. Monumental architecture was modest, associated with rituals and ancestor veneration, and became more public and massive starting in the Early Formative Period. Funerary evidence shows limited social differentiation. These results show that institutionalized inequality was not necessary for the development of complex societies in the Altiplano and contribute to ongoing debates on the variability and non-linear pathways of early complex societies in Andean archaeology.</p>