Today, computer systems play a central role in all aspects of human life, including in the operation of highly-critical infrastructures, for instance, in the domains of healthcare, transportation, and telecommunication. However, in spite of this pervasive presence of computer systems in our daily activities, many users feel reluctant in trusting them. In the majority of cases, this diffidence can be primarily due to the fact that systems lack a proper evaluation process guaranteeing their reliability and trustworthiness. In this chapter, we propose an overview of software security certification techniques. Then we look at some of the leading certification schemes that have been adopted by governments and the industry over the years.