A small body of recent research has shown that moral considerations are crucial in predicting the willingness to participate in a political protest. This insight suggests that beyond emotional and instrumental considerations, people also conceive of protest activity on ethical terms and may be motivated to participate in or refrain from it based on their personal moral values. Despite this growing recognition, there is still a substantial gap in our understanding of the conditions that prompt individuals to feel a sense of moral duty to protest. This limitation implies that moral duty is inherently important and that many demonstrators feel such an obligation. This paper seeks to fill this void by examining the various underlying circumstances that facilitate a sense of duty to participate in demonstrations. I argue that determining whether the perceived levels of duty among demonstrators vary as a function of individual and/or contextual characteristics is critical for advancing the existing scholarship on the role of moral duty in protest participation. To test these expectations, the paper builds a series of multilevel models using unique comparative survey data from the Caught in the Act of Protest: Contextualising Contestation (CCC) project. The dataset includes 15,793 individuals who participated in 75 street demonstrations across 9 European countries between 2009 and 2013. Preliminary analyses reveal that both individual and contextual factors, along with cross-level interactions, influence perceptions of the duty to protest. However, contextual elements highlight more relevant variations in the perceived duty among demonstrators, suggesting that the duty to protest may not be universal. These findings shed light on how protesters internalise moral norms that motivate them to participate in protests and, therefore, have significant implications for the existing duty-engaged framework of citizenship norms and the broader literature on political behaviour.