In this paper, we apply the Poisson, drift-diffusion, and Schrodinger solver coupled with the Monte Carlo method to study the in-plane carrier dynamics in the InGaN c-plane and nonpolar plane quantum well light-emitting diode device. Carrier diffusion, scattering, radiative recombination, and trapping by dislocation defects in the quantum well are studied. The impact of carrier dynamics on the internal quantum efficiency (IQE) in the quantum well with different indium compositions, dislocation densities, polarization effect, and interface roughness is studied. Our results show that (for dislocations densities in typical devices) due to the large radiative lifetime from the quantum confined Stark effect, nonradiative recombination caused by the dislocation defects plays a dominated role in limiting the IQE. In the nonpolar quantum well, the IQE is much better than in the c-plane case but is still strongly influenced by dislocation density. Our results show that to achieve 100% IQE, the dislocation density levels need to be lower than 106 cm−2 and 107 cm−2 for c-plane and nonpolar plane InGaN quantum well, respectively. Our results are also compared with published experimental work and have shown a good agreement.