Background: Dietary factors are associated with the development of irritable bowel syndrome (IBS) in adults, but no studies have ever investigated the relationship between dietary patterns and the risk of IBS among adolescents. Methods: In this cross-sectional study a total of 750 adolescent girls aged 12 to 18 years old were recruited using a random cluster sampling method from several schools in different areas of Mashhad city, Iran. A validated food frequency questionnaire (FFQ) and the modified version of Rome III questionnaire were administered to assess the participants' dietary intakes and IBS, respectively. Socio-demographic data and anthropometric variables were also obtained. Factor analysis was performed to identify major dietary patterns. Results: The dietary patterns of healthy, mix, and western were identified in this study. An inverse non-significant association was also observed between the healthy dietary pattern and IBS (OR: 0.83; 95% CI: 0.47-1.48). The relationship of IBS prevalence with mix and western dietary patterns was also non-significant. Conclusions: No statistically significant associations were found between dietary patterns and IBS among Iranian girl adolescents. Further studies, particularly longitudinal intervention studies with a larger sample size are required in this area.