The entropy of two-dimensional Lennard-Jones fluids is calculated from computer simulation results for the radial distribution function. The applicability of the first-order Weeks-Chandler-Andersen perturbation theory to this calculation and dependence of the entropy on the perturbation parameter are analyzed, and a simple analytical expression is proposed for the entropy. Finally, the physical connection between entropy and molecular order is made through the values of the radial distribution function and of the average number. of interparticle interactions.