A group of deaf and hard-of-hearing (D/HH) students at mainstream schools (N = 212) was investigated in a questionnaire-based survey using the Inventory of Life Quality of Children and Youth (ILC) and the Classroom Participation Questionnaire. The ILC data for the D/HH sample are for the most part comparable with the data from a normative hearing sample. Item-total correlations showed that the domains of school and social activities with peers were more important for the Health-Related Quality of Life (HRQoL) of the D/HH students than for that of the hearing students. The results also reveal differences in the HRQoL levels of the two samples, with the D/HH sample having higher scores for school experiences, physical and mental health, and overall HRQoL, though the effect sizes for the differences are small to moderate. Specific characteristics of the D/HH sample may be responsible for this result. There are also relationships between quality of life and perceived classroom participation in certain domains: Students who perceive classroom participation as satisfying have higher scores for quality of life in school, social contact with peers, and mental health. This also applied to the scores for global assessment and a summarized quality of life indicator.