Aim of the study: This cross-sectional study is aiming for investigating the relationships of the depth of curve of Spee with different Angle classes.

Materials and Methods: A sample of 240 study models were collected and scanned digitally to measure the depth of curve of Spee. The sample has been divided into 4 groups including: Angle Class I, Angle Class II Division 1, Angle Class II Division 2 and Angle Class III with 60 study models in each group. The depth of the curve of Spee has been measured from the left and right sides and the mean value of both sides was calculated.

Results: The measurement of curve of Spee showed significant differences between different classes (p<0.05). The highest measurements of curve of Spee are seen in Angle class II division 2 subjects followed by Angle class II division 1then Angle class I and the smallest measurements were seen in Angle class III subjects.

Conclusion: Curve of Spee can differ significantly with different Angle classes. Deep curve of Spee is usually anticipated in Angle Class II Division 2 followed by Angle Class II Division 1. Thus, it is important to anticipate the space requirement for levelling of curve of Spee in these cases.