Requirements validation is a critical phase of requirements engineering processes, which makes sure that requirements are correct, consistent, complete and accurate. Requirements validation is used in determining the right requirements, while verification determines that implementation is correct with respect to its requirements. The main objective of validation is to certify that requirement specification document is the acceptable description of the system, which is going to be implemented. Requirements validation techniques (RVTs) play pivotal role to detect possible defects in the requirements. RVTs can help in the completion of projects, within given schedule, budget and according to the desired functionality. The studies of six companies regarding requirements validation, is presented in this thesis. This study explores the requirements validation techniques that are presented in academia and practiced in industry as well. Interview studies are conducted in two countries, which is an attempt to find the usage of requirements validation techniques in both of the countries. The pros and cons of identified RVTs are discussed, along with it; the comparison of different RVTs with respect to the satisfaction level of specific RVT in terms of catching defects, time/schedule and cost is presented as well.