Background: Facial growth and development is crucial in orthodontic and forensic dentistry. Relating skull base parameters as foramen magnum (FM) size and shape to skeletal growth provides important indicators for craniofacial development. The study aimed to determine if there is a relation between the shape and dimensions of FM and anteroposterior (AP) skeletal relationship, and to predict skeletal class based on FM dimensions and shape. Methods: hundred and eleven CBCT scans were analyzed using Anatomage software assessing various skull parameters and FM shape and dimensions. All the measurements were evaluated in relation to AP skeletal relationship. Logistic regression (LR) analysis was performed to differentiate between class I and class II. Results: The oval shape is the most frequent FM shape across all classes, whereas the rounded and irregular shapes were common in Class III. Although the shape and dimensions of FM along with other cranial dimensions showed no significant correlation with skeletal classes, mandibular length, ramus height, and gonial angle were larger in class III. The FM index in the sample was of the narrow type (<82) with the highest rate in Class I (40.3%) and mean FM index of 79.09 ± 8.83. The LR model produced a modest overall correct classification of 67.44% (73.33% for class I, 60.98% for class II). The area under ROC curves of the model was equal to 0.751 which is considered acceptable. Conclusion: The study revealed no significant differences between the shape and dimensions of FM with AP skeletal relationship and skull parameters.