This study aimed to describe different approaches for the evaluation of the Oral health-related quality of life (OHRQoL) of preschool children and to discuss perspectives for future instruments. The OHRQoL is a concept that surpasses an exclusively clinical perception and includes functional, social, emotional, and environmental issues. The measure of OHRQoL represents a holistic approach for researchers and clinicians extending their visions beyond the mouth and understanding the entire context of the patient. Negative impacts of oral conditions on OHRQoL in childhood can reflect on health development, especially in a life stage marked by social and cognitive maturation. Instruments have been developed and cross-culturally adapted to evaluate the impact of oral conditions on the OHRQoL of preschool children and their families. Some features distinguish these instruments and influence their selection, such as: self- or proxy-report; generic- or specific-condition; long- or short-form, and less or more established used in literature. Moreover, theoretical framework, construct validation and availability should also be considered. Nine OHRQoL instruments for preschool children were included in the present literature review. They were created between 2003 and 2017 by developed countries in most cases. The shorter instrument has five items, and the larger has 31 items. Most of them are proxy-reported, generic-condition, and have been relatively well established in the literature. The diversity of instruments indicates the evolution of OHRQoL studies, but there are methodological issues still in need to be improved in future developments or cross-cultural adaptations, according to current psychometric evidence.