This dissertation presents three essays on foreign aid effectiveness. Chapter 1 presents the role of monitoring procedures in improving the effectiveness of foreign aid. It analyzes how monitoring procedures influence the government’s effort and improve the effectiveness of foreign aid. The chapter considers two cases, the case in which the donor has unrestricted aid budget and the case where the donor has a fixed aid budget. The main concern in this chapter is determining the optimal contract for the donor that maximizes the effectiveness of the aid given her aid budget when she dealing with aid-recipients in the presence of moral hazard problem. The model analyzes the monitoring procedures between two players, donor and recipient in a one...