Background Patellofemoral pain (PFP) is a common cause of knee pain. This condition can restrict daily activities by trying to avoid activities that aggravate their pain. This study aimed to determine the prevalence of PFP and knee pain and its associated factors among Saudi young adults. Methods A descriptive cross-sectional study was conducted in Saudi Arabia. A validated translated Arabic questionnaire was used. Data was collected through an online self-administered questionnaire. Saudi young adults of both genders aged between (18 to 40 years) were included. The mean ±SD was described for continuous variables, whereas categorical variables were reported using frequencies and percentages. The chi-square test was used for descriptive analysis. Results A total of 1558 subjects were enrolled in the current study. About 663 (42.6%) were males and 895 (57.4%) were females. Of the total participants, 718 (46%) were within the age group of 18 to 25. The overall prevalence of PFP among the current study participant was found to be 30.3%. The prevalence of PFP among males was found to be 31.4% and the prevalence of PFP among females was found to be 29.5%. The overall prevalence of knee pain among study participants was found to be 13.2% as 205 of the participants reported knee pain. The prevalence of knee pain among males was found to be 14% and the prevalence of knee pain among females was found to be 12.3%. The multivariate analysis included the following variables: age, gender, and marital status. The following factors predicted higher rate of PFP: being 18 to 25 years old (p-value < 0.001, odds ratio = 1), being 26 to 35 years old (p-value = 0.001, odds ratio = 1.689). Conclusion The prevalence of PFP and knee pains was found to be relatively high in Saudi Arabia. Age less than 40 years old was found to be associated with a higher prevalence of PFP and knee pain when compared to other age groups.