In this study, the effect of mill speed was investigated on the limestone and the clinker samples of Goltas Cement Factory (Isparta, Turkey) at batch grinding conditions based on a kinetic model. For this purpose, first, six different monosize fractions were carried out between 0.850 and 0.106 mm formed by a two-sieve series. Then, S-i and B-ij equations were determined from the size distributions at different grinding times, and the model parameters (S-i, a(T), alpha, gamma, and phi(j)) were compared for five different mill speed (fractional of mill critical speed; 55%, 65%, 75%, 85%, and 95%).