Calling for increased action on climate change, Fridays for Future (FFF) quickly gained momentum around the world and became highly visible through strikes and protests in more than 150 countries. Considering its scale and magnitude, questions about the impact of this newly emerging climate movement arise. This article is based on a survey investigating the perception of Swiss residents ( N = 1206) of how the FFF movement and Greta Thunberg’s climate activism changed their environmental awareness and behaviour. We found that the Swiss public by and large perceives Greta Thunberg and the FFF movement positively, and a considerable share of participants report that Greta Thunberg (30%) and the FFF activism (23%), respectively, positively influenced their environmental concern and behaviour. Structural equation modelling revealed that the strength of the behaviour change motivation depended mainly on how a participant evaluated the FFF movement and Greta Thunberg. The latter was influenced positively by general environmental attitudes, and education level and negatively by the acceptance of justifications for environmentally harmful behaviours. Participants reported environmentally positive changes most frequently in private sphere behaviours, particularly in the domains of mobility, consumption and waste, whereas few changes in public sphere behaviour were reported. Next to increased awareness and motivation gains, also the reinforcement of existing pro-environmental behaviour was reported. Although the influence on sympathisers was stronger, some of those sceptical of the climate strike movement also reported behaviour changes, indicating that the unconvinced have to some extent been reached.