On March 11, 2020, the World Health Organization declared the epidemic caused by COVID-19 a pandemic. Days later the world had to switch to the “online” mode of conducting businesses, including instrumental music instruction in schools. This study aimed to compare the motivation of music students in Austria before and after the transition to online learning and to find explanations for the quantity and quality of motivational regulation. Since hardly any scientific findings exist on online instrumental music instruction, the study, is based on following research questions: 1. Are students motivated at all to learn a musical instrument in a synchronous online setting? 2. What are the conditions for motivated learning in online instrumental instruction, and what are the reasons for the lack of motivation? The study compared two sample groups: one before online learning (N=856) and the other during online intervention (N=640). A comparison of both the groups was possible because both the surveys took place at the same music schools. Using data from an online survey designed on the basis of the self-determination theory, the study findings primarily indicate that intrinsic motivation in online learning was significantly lower, and extrinsic forms of motivation were higher than in the scenario before the COVID-19 crisis. Moreover, the satisfaction of basic needs (essential for motivational regulation) appeared to have decreased in online learning. Regression analyses showed that 39% of the variance of intrinsic motivation in online learning could be explained by social relatedness, the interest of the teacher in teaching, and age.