The study aimed to equate General Education Diploma results of physics exam in the Sultanate of Oman using Item Response Theory (IRT) and setting them in a common scale. In addition, the study aimed to find whether there is a difference in equating according to gender and the educational governorate using Equivalent Group Design or Random. The study sample included all of the General Education Diploma students who passed the physics exam in the academic years 2014/2015 and 2015/2016, with a total sample of (18966,17175) respectively. Two different copies of physics exam were used for the purpose of the study. The first one consisted of 40 items and the other was 36 items. The data was analyzed by Multilog 7.03 program, to estimate the parameters of the items and the abilities of examinees and also to check the IRT hypotheses. Moreover, the method of True Score Equating was used, and the results indicated close mean values between the true scores of the criteria exam and the equated scores of the new exam. The equation accuracy was checked by Equating Bias method. Descriptive statistics results showed close results between the equated scores of males and females across the two exam samples with the total equating. Furthermore, the descriptive statistics found similar results between the equated scores of the governorates (Muscat, Al Dakhilia and North Al Batinah) across the two exam samples with the total equating.