Alkylphenols (APs) received great attention in the past decade because they were on the priority hazardous substances list. The kinetics of a lab-scale moving bed biofilm reactor (MBBR) that was fed with synthetic wastewater containing 4-NonylPhenol (4-NP) and 4-tert-OctylPhenol (4-t-OP) was investigated in this paper. The MBBR reactor was evaluated under different APs, organic loading rates, and hydraulic retention times (HRT). The substrate removal rate was predicted with the first-order, second-order, Stover-Kincannon, and Monod substrate removal models. 4-NP and 4-t-OP pollutants were removed in the different percentages of 87.1 to 99.9% and 83.2 to 99.9%, respectively. Biokinetic parameters, like Y, K-S, k, (max), and k(d), that would be favourable to design an MBBR were evaluated. Based on the results, the second-order (Grau), Stover-Kincannon, and Monod models were observed to be the most suitable for this reactor. These models showed high correlation coefficients of about 99.6, 99.1, and 92.9%, respectively. Consequently, these models could be utilized in anticipating the performance and design of MBBR reactors.