<p>This paper describes a dataset containing field measurement data from classrooms in Belgium. The dataset comprises of survey responses, indicating occupants’ satisfaction with the indoor environmental quality (IEQ) (i.e., thermal, indoor air quality, visual, acoustic and overall IEQ conditions), measurements of the indoor environmental conditions in the classroom during heating and intermediate season, and contextual variables like occupant location in classroom. Data were collected in three educational case studies: three classrooms in a secondary school (Case 1), seven primary school classrooms (Case 2), and a university lecture room (Case 3). The full dataset consists of 6834 satisfaction assessments collected from 321 unique occupants in classrooms, merged with corresponding measurements of the classroom IEQ. The dataset benefits the research community since a longitudinal dataset of this size on occupants’ satisfaction in classrooms is unavailable at this moment. The dataset can serve as a training or validation dataset for novel comfort models, a basis for statistical analyses to establish a causal model or to examine inter- and intra-individual differences in occupant satisfaction.</p>