The aim of this study was to explore subgroup effects by high and low socioeconomic position (SEP) of three previously conducted, effective European interventions. Reanalyses stratified by SEP were conducted by the research groups of each study. All studies were school-based: two multi-component interventions targeting intake of fat or fruit and vegetables (FV), and a free breakfast initiative. Computer-tailored advice affected fat intake among low, but not high SEP girls after 1 year. A multi-component intervention affected the total FV intake in both SEP groups, vegetable intake in low SEP and fruit intake in high SEP across three countries after 1 year, whereas free fruit affected total FV and fruit intake equally in both SEP groups in one country after 2 years. Providing a free healthy breakfast increased consumption of healthy food items only in the low SEP group. Reanalysing intervention studies by SEP is a quick and easy way to explore patterns in effects by SEP across interventions. Providing healthy food might be a promising strategy for decreasing social inequalities.