Copyright © 2018, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Chapter 2 31 DOI: 10.4018/978-1-5225-5091-4.ch002 ABSTRACT The optimization problems are the problem of finding the best parameter values which optimize the objective functions. The optimization methods are divided into two types: deterministic and non-deterministic methods. Metaheuristic algorithms fall in the non-deterministic solution methods. Prey-predator algorithm is one of the well-known metaheuristic algorithms developed for optimization problems. It has gained popularity within a short time and is used in different applications, and it is an easy algorithm to understand and also to implement. The grey systems theory was initialized as uncertain systems. Each grey system is described with grey numbers, grey equations, and grey matrices. A grey number has uncertain value, but there is an interval or a general set of numbers, within that the value lies is known. In this chapter, the author will review and show that grey system modeling is very useful to use with prey-predator algorithm. The benchmark functions, grey linear programming, and grey model GM (1,1) are used as examples of grey system. INTRODUCTION The grey systems theory is designed to study uncertain systems which focus on the incomplete information that is due to small samples and poor information (Julong, 1982, 1989; K. Li, Liu, Zhai, Khoshgoftaar, & Li, 2016; Liu & Forrest, 2010; Liu, Yang, & Forrest, 2017). Grey systems have incomplete parameters, structure, or boundary of systems (Liu & Forrest, 2010; Y. Yang, 2010). They have been Grey Optimization Problems Using Prey-Predator Algorithm Nawaf N. Hamadneh Saudi Electronic University, Saudi Arabia