Objective. Across nationwide rollout of COVID-19 vaccination, people in Belgium differed widely in their vaccination intention. In the present study, we examined (a) how people’s vaccination intentions changed during the vaccination rollout and (b) whether changes in motivation (i.e., autonomous, controlled, and distrust-based (a)motivation) predicted changes in vaccination intention, thereby taking into account people’s vaccination intention at baseline.Methods. Using four subsamples of participants who were vaccinated at different time points (ntotal = 10,799) between December 2020 and June 2021, we used latent Change Modeling and Latent Growth Curve Modeling to examine the associations between initial levels and changes in vaccination motivation and vaccination intention. Results. Across subsamples, changes in vaccination intention were found to be qualified by changes in motivation. An increase in autonomous motivation was related to a positive shift in vaccination intention, while an increase in both controlled motivation and distrust-based amotivation was related to a negative shift in vaccination intention. Moreover, autonomous motivation predicted especially an increase in vaccination intention among those initially low in vaccination intention, whereas an increase in either controlled motivation or distrust-based amotivation especially predicted a decrease in vaccination intention among those initially high in vaccination intention . Conclusions. Findings suggest that a growing sense of ownership and a reduction in distrust is critical for individuals to develop a stronger intention to get vaccinated, particularly when people had initially low vaccination intentions. We discuss conceptual, methodological, and practical implications.