This study aimed to develop a measurement tool assessing the anxiety levels of university students in a biology laboratory class. As a result, the findings obtained from the analyses show that B-LAS has high reliability criteria. Moreover, the fact that the scale has just been developed and has no other example abroad can be considered as both a limitation and advantage. According to the results obtained from this scale developing study, it can be said that the scale is ready to be used and can be validly and reliably used to determine students’ anxiety level for the biology laboratory class