This study investigated the relationships between conformity behavior and daily communication style. In total, 159 junior high school students participated in the investigation. Their internal conformity tendencies and external conformity tendency were measured by a conformity behavior scale. We examined participants’ communication styles using hypothetical situations. Participants were presented with three daily communication situations and asked what they would usually say. The results showed that students with a non-assertive communication style were more likely to conform to others than those who have an aggressive communication style. Especially, non-assertive female students tend to conform externally more than aggressive or assertive female students. This type of student might inhibit self-assertion to concern their friends.