This document describes a set of useful activities, tasks, methods, and practices that acquirers of software and related services from unrelated (external) suppliers can apply to help ensure an efficient and effective acquisition of software or software services. These practices can be applied in competitive and in sole source procurements, regardless of the type, size, complexity, and cost of the acquisition. The document can be applied to software that runs on any computer system regardless of its size, complexity, or criticality. The software supply chain can include integration of off-the-shelf (OTS), custom, software as a service (SaaS), or open-source software. Software services can include software development and sustainment (maintenance), integration, verification (testing) and operation. Security and safety are included as attributes to be considered during the acquisition. However, specific requirements for acquisition of information assurance (security), safety, and cloud services are not included.