To test whether countermarketing messages for sugary drinks lead to lower intentions to consume sugary drinks and less perceived weight stigma than health education messages. In August 2023, we conducted an online randomized controlled trial with US adults (n = 2169). We assessed the effect of countermarketing messages, health education messages, and neutral control messages on intentions to consume sugary drinks and perceived weight stigma. Both countermarketing messages (Cohen = -0.20) and health education messages ( = -0.35) led to lower intentions to consume sugary drinks than control messages (s < .001). However, both types of messages elicited more perceived weight stigma than control messages (s = 0.87 and 1.29, respectively; s < .001). Countermarketing messages were less effective than health education messages at lowering intentions to consume sugary drinks ( for countermarketing vs health education = 0.14) but also elicited less perceived weight stigma than health education messages ( = -0.39; s < .01). Countermarketing messages show promise for reducing sugary drink consumption while eliciting less weight stigma than health education messages, though they may need to be refined further to minimize weight stigma and maximize effectiveness. ClinicalTrials.gov NCT05953194. (. Published online ahead of print October 3, 2024:e1-e11. https://doi.org/10.2105/AJPH.2024.307853).