The purpose of the study was to determine the level of learning boredom during online mathematics learning for class X at SMK Negeri 1 Kalianda during the Covid-19 pandemic with a descriptive qualitative method. The sample selection using the purposive sampling technique was considered effective and in accordance with the criteria determined by the researcher. Thus, the sample used was 38 students. Data was collected by means of library research and distributing questionnaires on the boredom of learning mathematics online via WhatsApp. The steps of data analysis were carried out by 1) determining the general description of the questionnaire results, 2) grouping student answer scores based on online learning boredom level intervals and 3) interpreting the results of student answers based on the percentage of each indicator. The results showed that class X students at SMK Negeri 1 Kalianda experienced learning boredom with 10% in the low category, 74% in the medium category and 16% in the high category. This means that the majority of class X students at SMK Negeri 1 Kalianda experience boredom learning online in the moderate category, especially in mathematics. The indicator that has the highest percentage level is the loss of motivation by 75%, followed by the cognitive fatigue indicator at 71% and the emotional exhaustion and cognitive fatigue indicators at 69%. It can be concluded that the increase and decrease in mathematics learning outcomes can be caused by one of the factors, namely the boredom of learning carried out online.