Today, organisations are increasingly using project-based activities, as projects can aid organisations to deal with unique and complicated assignments, as well as achieving strategic and operational goals. Two extensive project management methodologies exist, those being Traditional Project Management and Agile Project Management. Agile methods trademark change, adaptability, and flexibility, and are today used across industries and business, as the characteristics of the methodology make it suitable in today’s dynamic business environment. Even though projects are increasingly being used, it is inconsistent with the remarkably low project success rates found. It has been found that only 30 per cent of projects are successful within the technology field. Consequently, this stress the need to understand the inconsistencies found as well as generating suggestions for how to improve them. It is arguable that the inconsistencies may be caused by the difficulty to define project success. Researchers argue that the definition of project success is difficult to pinpoint as it varies depending on both individual perspectives and situational factors such as the organisation and the project type. It is also questionable whether or not appropriate methods have been used to evaluate the success of a project, and that the use of inappropriate methods may have contributed to the low success rates. Researchers argue that the traditional way of evaluating project success, by adhering to schedule, cost, and scope, is outdated and incomplete, and some have therefore developed new models that they consider more accurate for evaluating project success. One of these researchers is Highsmith, one of the founders of the Agile Manifesto. Highsmith has developed the Agile Triangle to better correspond to the agile trademarks of change, adaptability, and flexibility when evaluating success on agile projects. This study aimed to contribute with new insights into theoretical and practical aspects of agile project success by studying agile project success from a project manager perspective. This thesis also aimed to generate an understanding of project managers’ perception of the Agile Triangle as a success criterion. We interviewed seven Swedish project managers who have all worked with agile projects. After thoroughly analysing the results we could create a definition of agile project success as well as develop an Agile Project Success Criteria Model, representing the view of Swedish project managers. Agile project success was defined as a project that generates value in a sustainable manner. The agile project success criteria found important within this study are: Value, Team Success, Quality, Business Benefits, and Constraints. It was also found that Flexibility, even though it should not be included as a success criterion itself, is still a key ingredient when using Agile Project Management methodologies, as it affects all important success criteria. These findings highlight the insufficiency of the Agile Triangle as a success criterion, as Team Success and Business Benefits, criteria additional to those within the Agile Triangle, were found important. It was also found that the project managers question the practical applicability of the Agile Triangle and consider it to be similar to the Iron Triangle.