Volleyball is one of the most popular sports for people of all ages because children and adults both males and females are familiar with this game. As a game, volleyball goes through continuous development and innovation in terms of techniques and tactics. Volleyball is a type of sports game that requires skill and mastery of technique. Athletes are required to master the technique in order to be able to play effectively and efficiently. In volleyball, there are basic techniques that must be mastered. To assess the mastery of volleyball techniques, a valid and reliable instrument is needed. However, there is no instrument that specifically assesses young athletes’ skills in volleyball. Therefore, in this present study, the researchers aimed to develop an instrument to measure young athletes’ volleyball technique mastery. The Research and Development design was used in this study. A small-scale tryout was conducted to evaluate the instrument developed. Based on an assessment carried out by volleyball coaches, the instrument obtained an average score of 87.5%. Meanwhile, based on the large-scale tryout, the instrument obtained an average score of 85.42%. It indicates that the developed instrument is “highly feasible” to be used to assess young athletes’ basic technique mastery in volleyball. The product of this study is an instrument to assess young athletes’ mastery of basic techniques in volleyball.