Background To evaluate oral health-related quality of life (OHRQoL) over a period of five years using the Oral Health Impact Profile (OHIP-14) questionnaire in a population of Swedish adolescents born preterm and full term. Methods In a longitudinal study of adolescents aged 12-14 and 17-19, changes over time in OHRQoL were measured by using OHIP-14. The OHIP-14 score, self-reported chronic illness, temporomandibular disorder (TMD pain) and subjective orthodontic treatment need were compared between 98 extremely and very preterm born (< 32 gestational week) and 93 full-term controls (>= 37 gestational week) at two ages. The chi-square test was used for comparisons within the extremely-, very-, and full-term control groups, and to contrast the differences of mean scores of OHIP-14, the ANOVA test was used for comparisons within the study groups of extremely preterm, very preterm and full term-born adolescents. Results All adolescents reported a good self-perceived OHRQoL. No significant differences in the comparisons of the total mean scores were revealed between the groups, between gender or in domain-specific scores over the 5-year period. Very preterm adolescents with reported chronic illness at 12-14 years of age showed significantly higher mean scores of OHIP-14 compared with those without chronic illness (p = 0.015). At age 17-19, significantly higher mean scores of OHIP-14 were reported by very preterm adolescents with TMD pain compared to those without TMD pain (p = 0.024). Significantly higher mean scores of OHIP-14 were found among the extremely preterm (p = 0.011) and very preterm born adolescents (p = 0.031) with a subjective need of orthodontic treatment compared with those without orthodontic treatment need. Conclusions Poor OHRQoL measured with OHIP-14 in very preterm adolescents aged 12-14 was related to chronic illness and aged 17-19 to TMD pain. In addition, extremely and very preterm-born adolescents with subjective orthodontic treatment need at 17-19 years of age also reported poor OHRQoL. To improve the dentist-patient relationship and achieve more successful treatment results, it is important for dental clinicians to understand the impact that chronic illness, TMD pain and orthodontic treatment need has on OHRQoL in preterm-born adolescents.