The present work aims to analyze in an exploratory manner the contours of collegiality for and in the Federal Supreme Court. In this sense, the work seeks, at first, to outline the general normative considerations that precede the theory of collegiality both from the institutional perspective as a mechanism of decisionmaking engineering, thus seeking to investigate: what, how and why collegiality? In a second moment, the work explores the complex institutional design of the Brazilian Supreme Court to understand the different paths that lead to the collegiality, as well as the diverse collegiate bodies within a single court. Finally, the work investigates the Court members as instruments of collegiality and what are the different meanings that collegiality achieves from an investigation of the votes of members in plenary decisions.