The pyrolysis kinetics of a mixture of the four principal papers (uncoated and coated printing/writing papers, newsprint, and tissue paper) in municipal solid waste (MSW) was investigated with a thermal gravimetric analysis (TGA) reaction system. The experiments were carried out in a nitrogen environment over the temperature range of 450 to 900 K at various constant heating rates of 1, 2, and 5 K min(-1). The results indicated that there were two principal reactions in the TGA curves as distinguished by the two significant and distinct mass changes over the experimental conditions. The pyrolysis of a paper mixture can be adequately described by a two reaction model. The effect of interaction between the components of a paper mixture on the pyrolysis rate was insignificant. The results for the pyrolysis rates of paper mixtures with slow heating rates can be represented by the weighting sum of the corresponding pyrolysis rates of the components of papers in MSW. The experimental results were satisfactorily fitted by the proposed chemical reaction kinetic equations and able to provide useful data for the design of a pyrolytic processing system for the waste papers in MSW.