Tribal water rights and instream flows for species listed under the Endangered Species Act (ESA) have been a source of tensions in the western United States, particularly when tribes have undetermined water rights to support tribal fisheries listed under the ESA. Understanding the mechanics of past tribal settlements and their strengths and weaknesses in resolving disputes over instream flows for tribal trust fisheries listed under the ESA will allow parties involved in negotiations to evaluate whether similar provisions should be incorporated into future settlements. A review of the 27 congressionally approved tribal water settlements for instream flow and ESA provisions revealed that instream rights were either established as junior rights or reallocated from existing rights. The ESA was a factor in many of the settlements; however, only one actively incorporated ESA tools as part of the benefits of the settlement. After this preliminary evaluation, a comparative analysis framework with 28 criteria for evaluating environmental conflict resolution was applied to the Nez Perce Water Rights Settlement and Pyramid Lake Paiute Water Rights Settlement to identify strengths and weaknesses of using tribal water settlements as a means to resolve disputes involving instream flow claims. From my analysis, I conclude that tribal water settlements offer unique opportunities to shift the status quo and address historic inequities while minimizing harm to existing water users; however, settlement agreements may not result in an outcome that reduces conflict without a concerted effort to establish a fair process and minimize the impacts of the agreement on other parties. Furthermore, despite the many benefits of settlement agreements, since they have not delivered time-immemorial rights for fisheries, other options will likely be a continued consideration for tribes seeking to restore fisheries. However, while litigation presents a risky though lucrative outcome, rights under state law are in line with what has been granted in settlements. Given the time, effort and cost associated with settlements, I suggest that since tribal water right settlements generally use state tools to establish instream flows, states and tribes may reduce future conflict by proactively working together to establish instream flows through existing state water reallocation mechanisms. / Graduation date: 2012