Microwave heating of single lap adhesive-bonded joints with polypropylene adherends having very low loss factor was studied. The adhesive joint was heated in an applicator based on a standard rectangular waveguide WR340 operating at 2.45 GHz frequency in the dominant TE10 mode. The temperatures at different locations in the adhesive layer were measured. A two-dimensional numerical model was developed to determine the temperature distribution in the adhesive layer of the modelled joints during the process. Finite-difference time-domain method was used for solving the governing differential equations. The experimental and the simulation results showed that the numerical model was reasonably accurate to represent the curing process.