Social media is considered a powerful tool to spread information about sustainable food, with both positive and negative impacts on sustainable food behavior. Thus, this exploratory study aimed to investigate the topics related to the hashtag #sustainablefood and their sources on “X.” Posts in English containing the hashtag #sustainablefood, between June 1st, 2021 and May 30th, 2022, were retrieved using a combination of the Twitter API and the social networking scraper SNS in Python. Characteristics of users generating the posts were retrieved from their profiles and analyzed using content analysis. Results indicated that companies and media organizations led the communications related to #sustainablefood, whereas regular consumers were a minority of the users posting content on the topic. In addition, associations between hashtags were analyzed with network analysis and using hierarchical cluster analysis, nine main topics were identified: agriculture, climateaction, climatechange, environmental, farm, plantbased, vegan, innovation, and foodtech. Hashtags on each topic varied by source, producing different messages. Plantbased and climatechange were identified as key bridging hashtags via betweenness centrality. This study contributes to understanding how sources use hashtags differently regarding sustainable food on social media and highlights the importance of analyzing post sources to avoid misattributing content to regular users.