Background and objective: One of the greatest challenges for the orthodontist is to select the correct ligation system to get optimum results. Ligation method refers to the means by which an arch wire is held inside the bracket. Recently developed ligation methods have been designed and built directly to brackets. The purpose of this study was to evaluate the effects of different ligation systems on arch expansion, incisor inclination and with regard to treatement duration in patients with mild to moderate crowding in maxillary arch. Materials and methods: Sixty patients were selected from a pool of patients amenable to non-extraction treatment in maxillary arch and those who satisfied other inclusion criteria. Patients were randomly allocated to three different ligation systems with equal sample size of 20 each. The model cast were evaluated for assessing maxillary arch changes, incisor inclination, and arch expansion. Analysis of covariance (ANCOVA) was used to compare the influence of the 3 bracket systems. Results: We found that the type of bracket had sgnificant effect on many of the transverse dimensional changes in maxillary arch No statistical significant difference in incisor inclination changes. The use of passive or active self-ligating bracket reduces the treatment duration. Conclusion: Non extraction treatment of crowding in maxillary arch with different ligation methods showed that compared to conventional system use of self-ligation bracket might be mechanically more efficient and had greater magnitude of expansion.