Book excerpt: Given the increasing need to optimize resources sustainably, decision-makers face challenges in analyzing and considering the numerous factors involved. This book makes an effort to present and concentrate on the challenges in decision-making processes for green and sustainable engineering. Through a collection of case studies such as evaluation of waste assessment and drainage system, sustainable building assessment, renewable energy selection, materials and manufacturing process optimization, and crop pattern influence in environmental and economic conditions, readers can learn how to apply cutting-edge Multiple-Criteria Decision Making (MCDM) methods in addressing complexities involved in the decision-making process.