States are increasingly developing and deploying large scale surveillance and AI-enabled analytical capabilities. What is uncertain, however, is the impact this surveillance will have. Will it result in a chilling effect whereby individuals modify their behaviour due to the fear of the consequences that may follow? Understanding any such effect is essential: if surveillance activities interfere with the processes by which individuals develop their identity, or undermine democratic processes, the consequences may be almost imperceptible in the short term but profound over the long term. Currently, surveillance-related chilling effects are not well understood, meaning that insufficient weight is given to their potentially society-wide impacts. This article seeks to help redress this balance. Drawing on empirical research in Zimbabwe and Uganda it highlights how State surveillance has chilled behaviour, with significant implications for rights essential to individual development and democratic functioning, specifically the rights to freedom of expression and to freedom of assembly. Importantly, this qualitative research identifies a pattern of common themes or consequences associated with surveillance in general, allowing us to move beyond hypothetical or individual experiences, and providing a greater understanding of the nuances of surveillance-related effects that can help inform decision-making surrounding large scale digital surveillance.