A useful model has been developed for the optimization of fiber-coupled laser-diode pumped lasers by including the effect of pump beam quality into the mode overlap integrals. Simple analytical expressions for the optimum pump spot size, the threshold pump power, and the slope efficiency have been derived by fitting the numerical results of the mode overlap integrals to an analytical function which is in terms of laser-diode beam quality and properties of the active medium. With these expressions the optimum mode size and the maximum output efficiency can be calculated for arbitrary values of pump beam quality and input power. Also, we obtained an analytical expression to relate the required input power and pump beam quality to the desired output efficiency and properties of an active medium. The present model provides a straightforward procedure to design the laser resonator and the optical coupling system for output optimization. To illustrate the utility of the present model, a Nd:YAG laser pumped by fiber-coupled laser diodes is considered and optimized. Experimental results have shown a fairly good agreement with the theoretical predictions.