As countries around the world rolled out the COVID-19 vaccines to the public in 2021, many countries faced more vaccine hesitancy and weaker demand for the vaccine than anticipated. In response, governments, public health agencies, and health behaviour researchers scrambled to design and implement programs and strategies to bolster demand. Financial incentives and other behaviourally-informed strategies like exclusivity prompts and social proof messaging were promising approaches, based on prior evidence from other health behaviours and vaccination campaigns. In this talk, I will review the theory motivating the scramble for behavioural solutions to COVID-19 vaccine demand, discuss several different intervention designs that were tested (e.g., regret lotteries, “reserved for you” messages), and summarise the results from multiple studies in diverse settings, including several that I helped to design and implement. While there are examples of positive effects in some studies, the preponderance of the evidence suggests that the potential for behavioural insights to boost the COVID-19 vaccine roll-out was not fully realised. I will conclude with both research and practice implications for COVID-19 and other vaccination programs going forward.