Framing is pervasive in public international law. International legal norms (incl. soft law) and international politics both inevitably frame how international actors perceive a given problem. Although framing has been an object of study for a long time - be it in domestic or international politics - it has not been systematically explored in the context of social cognition and knowledge production processes in public international law. We aim to close this gap by examining the implications of framing effects for preference and belief formation in specific settings in public international law. By looking at issue framing in addition to equivalency framing (which includes most well-known gain-loss framing effects), we broaden the scope of framing effects as traditionally studied in behavioral law and economics by also including findings from research in political communication. In the first part of this chapter, we provide an overview of the experimental evidence of both types of framing, show how it has already been incorporated into neighboring disciplines to public international law, and untangle the difference between preference reversals and a change in beliefs. In the second part, we identify typical situations in public international law where framing effects play an important role in social cognition and knowledge production processes. Without claiming to be exhaustive, we focus on international negotiations, international adjudication, global performance indicators, and norm framing.