This work focuses on understanding the effect of methyl substituent on the curing of bisphenol-arylamine-based benzoxazines through investigating the curing kinetics of bisphenol A-based benzoxazines (BA-a and BA-35x) and bisphenol C-based benzoxazines (BC-a and BC-35x) using non-isothermal differential scanning calorimetry (DSC). Kissinger, Ozawa, Friedman, Starink and Malek methods were utilized to determine the kinetic parameters and built the kinetic models. BA-a, BC-a and BC-35x show only one dominant autocatalytic curing process, whereas, BA-35x exhibits two curing processes, i.e., the generation of arylamine Mannich at low-temperature (Reaction (1)) and the formation of phenol Mannich at elevated temperature (Reaction (2)). With the aid of Fourier transform infrared, the possible curing routes were also proposed. The results may contribute to a better understanding the curing of bisphenol-arylamine-based benzoxazines and the formation of arylamine Mannich bridge structures.