Many school children experience overweight and obesity due to consumption of unhealthy snacks that contain high energy, fat, and sugar. Unhealthy snack consumption behavior occurs because children lack knowledge and attitudes about healthy snacks. This research aims to determine the effect of game card-based nutrition education on knowledge and attitudes of elementary children about healthy snacks at SDN Pakis VIII Surabaya. This type of research is quasi-experimental with two groups pretest-posttest design. The total sample was 51 students, namely 27 students as a group who were given game card-based nutrition education and 24 students as a control group with PowerPoint slides. Sampling used purposive sampling technique. Data collection was carried out by completing the pretest, posttest, questionnaire before and after nutrition education. Data analysis used the independent sample t-test. The results of the research showed that the knowledge value was significantly different between the groups with game cards and PowerPoint slides (p=0.017). This proves that game card-based nutrition education influences elementary school children's knowledge about healthy snacks at SDN Pakis VIII Surabaya. Apart from that, a significant difference in attitude value was also found between the two groups (p=0.024). This also proves that game card-based nutrition education influences elementary school children's attitude about healthy snacks at SDN Pakis VIII Surabaya. It is hoped that health promoter/UKS officer can implement game card-based nutrition education, especially targeting elementary children to support the consumption of healthy snacks and overcome overweight and obesity.