Objectives: ABO blood groups have been shown to be associated with different diseases. Very few studies have attempted to detect the association of ABO blood groups with obesity. The goal of this study is to find any potential relation between ABO blood groups and high body mass index (BMI) among a Saudi population, which may contribute to underlying genetic disorders. Methods: A cross-sectional descriptive study was conducted using a structured questionnaire that contained general demographic data, including weight, height, type of ABO blood group and the participants' opinion, to determine the association between the ABO blood groups and obesity. Results: Our study included 1171 participants, including 596 (50.9%) women. A plurality of participants' ages (47%) was between 15 and 25 years. The prevalence of obesity was 35.7% in men and 20.3% in women, while the prevalence of overweight was 30% in men and 25.3% in women. Blood group O was reported to be the most common blood group (46%), followed by blood group A (31.4%), while blood groups B and AB were found in 16.1% and 6.5% of participants, respectively. The prevalence of obesity (BMI ≥ 30) among participants based on blood group O, A, B, and AB was 13.7%, 9%, 4.8%, and 2.2%, respectively. There was no statistically significant difference between the prevalence of obesity or high BMI and ABO blood groups. Conclusion: Overall, our study did not show a significant relation between overweight and obesity and ABO blood groups. However, the elevation of the prevalence of overweight and obesity, mainly among the younger generations of the Saudi population, requires more awareness and educational programs.