Extracurrucular activities are activities outside of school hours and is an additional lesson for students which is deepening, repeating and training students about certain knowledge. But the determination of extracurricular is entirely left to the students, so sometimes students just follow along, the selection of extracurricular fields at school is sometimes not due to one’s own desires or interests to choose the extracurricular fields that is followed. The purpose of this research is to clustering data on academic scores and interest of Junior High School 4 Kemangkon students using the K-Means method, optimize the number of clusters using the elbow method, and calculate the error value of each clusters using Sum of Squared Error (SSE). The results showed that there were 4 groups of students in 7th grade and 3 groups of students in 8th grade based on academic abilities and interests.