Globally, the organic food market is the most successful green market. Young consumers, the decision-makers of the future, are perceived as being more environmentally concerned than older cohorts. The aim of this study was to consider young consumers’ attitudes and behaviours concerning organic food, where the organic food market in the UK is more mature than in Poland. Empirical research was conducted using a web-based survey questionnaire (CAWI) with consumers (n = 973) in both countries. The associations between four constructs (general pro-social attitudes, green consumption values, receptivity to green communication, and buying behaviour) were considered using CB-SEM. We extended the model with two new constructs to explain young consumers’ purchases of organic food. UK respondents are significantly more conscious green consumers with higher environmental attitude intensity than Polish residents. Intensity of pro-environmental attitude components influences directly and indirectly the choice of organic food. People with a higher intensity of pro-environmental attitudes are significantly more likely to choose organic food. Perception of organic food influences purchases only in Poland. The components of pro-environmental attitudes and perception of organic food alone do not explain the variability in behaviour, despite a good fit of the model. This suggests that other independent variables may be of influence.