In this study, we explored which executive functions (i.e., mental skills) help people understand metaphors better. Participants were given metaphors that were either familiar or new and were asked to interpret them in different contexts, some of which supported the understanding of the metaphor while others did not. To examine their executive functions, we tested participants with seven different neuropsychological tests. We used a method called the drift–diffusion model to analyze how participants responded. This model helps us understand the decision-making process in a detailed way. We found that participants who quickly understood metaphors performed well on a specific test called the Controlled Oral Word Association Test (COWAT)-Semantic, which measures a person’s interference control capabilities. Participants who did well on the COWAT-Semantic test demonstrated higher drift rates, indicating that they processed information more efficiently. This finding suggests that the ability to ignore irrelevant information (interference control) aids in understanding metaphors. Our analysis also showed that whether a metaphor was familiar or not was more important in the decision-making process than the context. In summary, we showed that the ability to control interference is important for understanding metaphors.