This study addressed potential differential effects of EF training as a function of language background. Training monolingual children with EF-fostering challenges and feedback may support them more than multilinguals, who face comparable challenges when switching languages. We assessed monolingual (n = 110) and multilingual (n = 91) 6-year-olds from Switzerland (N[subscript total] = 201, 101 female) for inhibition and shifting pre- and post-training using the Hearts and Flowers task. Children were assigned to one of three conditions: training on an EF task with feedback (n = 68), without feedback (n = 68), or on a control learning task (n = 65) for 12 sessions over 6-8 weeks. Results showed no differences between monolingual and multilingual children at T1. At T2, however, monolinguals outperformed multilinguals in inhibition with feedback and in shifting without feedback. Overall, monolinguals showed greater improvement than multilinguals. These results suggest monolingual children may benefit more from EF training, highlighting the need for tailored programs for monolingual and multilingual children.