In the context of the current post crisis world economy, improving trade capacity of developing countries is crucial for overall global development. Developing countries, and in particular least-developed countries (LDCs), continue to face supply-side constraints and lack trade-related infrastructure, which constrain their ability to implement and benefit from World Trade Organization (WTO) Agreements and expand their trade. The Aid for Trade initiative was conceived in this context to both mainstream trade into the broader national development strategies of the beneficiary countries and to enhance trade capacity of the developing countries. In this context, this study aims at conducting a detailed country case study on the development impact assessment of two selected aid for trade projects in Sri Lanka based on key five principles of evaluation.