Open source software development (OSSD) is a promising alternative for synthesising agile and plan-driven (e.g., waterfall) software development methodologies that retains most benefits of the two approaches. We contrast the traditional systems development life cycle approach, more recent agile software development methods, and OSSD. We compare the first two approaches with OSSD, highlighting its synthesis of benefits from both, with unique benefits of its own, offering solutions to areas where the other methodologies continue to face difficulties. OSSD is highly responsive to user needs, and potentially draws talent from a global team of developers. OSSD is a relatively low-risk methodology with potentially high return on investment. While not appropriate for all applications, especially those where the needed applications are extremely idiosyncratic to one company, it is nonetheless a valuable asset in an organisation’s portfolio of software development solutions.