Supplier Selection Process is multi-objective in nature; that is, typically more than one criterion needs to be considered in selecting the supplier and monitoring their performance. Numerous Multi-criteria decision making (MCDM) approaches have been proposed for Supplier Selection process in the literature, including the Data Envelopment Analysis (DEA), Analytical Hierarchy Process (AHP), Analytical Network Process (ANP), Fuzzy set theory, Mathematical modeling, etc. This book is aimed to provide a broad review of supplier selection problem, which includes various supplier selection criteria and some MCDM approaches for supplier selection. Some case studies are also reported to quantitatively illustrate the supplier selection process.