Effective and efficient use of power systems is directly related to the quality of the distributed power. Power quality should be monitored, and various analyses should be made to provide full control over the network. The importance of the power quality is clearly understood when the number of consumers in distribution systems is considered. When handling the distribution systems, it is seen that the distributed generation resources (DGS) may have positive and negative impacts on power quality. Increasing the presence of DGSs in power systems requires evaluation of their effects on the network. In this study, we aimed to examine the effects of DGSs on power quality through indices. The response of the power quality before and after the integration of distributed generation into the distribution system was evaluated using voltage variation and total harmonic distortion (THD) indices. Various simulation studies have been carried out on a real test system at different harmonic levels for THD, voltage variation, related power quality variation indices, and system indices for THD to be calculated. It has been observed that the indices considered are important to analyze the power quality of a distribution network in the presence of DGSs. The results show that the impact of harmonics and voltage drop can be reduced with properly located and increased rated power of DGSs.