Oral health-related quality of life (OHRQoL) is expected to be multidimensional. However, it is unknown what these dimensions are. This study aimed to explore the dimensional structure of OHRQoL using experts' opinions. A conceptual model of oral health with seven dimensions (functional limitation; physical pain; psychological discomfort; physical, psychological, social disability; handicap) was provided to 14 health care professionals. They assigned each of 49 items of an OHRQoL questionnaire, the Oral Health Impact Profile (OHIP), to the seven model dimensions. All 49 items could be assigned to one or more dimensions of OHRQoL. All seven dimensions of the conceptual model of oral health were identified: Functional limitation appeared 14 times, physical pain eight times, psychological discomfort 12 times, physical disability once, psychological disability four times, social disability nine times, and handicap once. This supported a seven-dimensional model of OHRQoL. However, when items were grouped into clusters with unique content, a smaller model appeared with the dimensions oral functions, orofacial pain, psychological impact, and social impact.