Many succeed academically through traditional assessment, but all students are disadvantaged by the one-size-fits-all, mechanistic approach which gives little consideration to the relational side of learning. This demands correction through a holistic philosophy of learning, where the learning environment caters for personal and social as well as academic development. More insidiously, traditional summative assessment obstructs the development of self- reliance, inculcating an over-reliance on ‘authority’ (teachers, examiners). New skillsets are needed by the 21st century, self-directed, lifelong learner. Teacher-directed assessment must defer to collaborative, interdependent, empowering, partnership based assessment, to maximise knowledge, work and life outcomes, benefiting individual and society. This study was conducted with a random selection of classes, including primary and secondary schools, early school leavers, senior learners and tertiary students. It shows that, when applied with care, peer- and self-assessment can serve as a summative and formative assessment tool, bringing additional benefits including self-reliance, critical thinking, decision-making, reasoned judgement and improved inter- and intrapersonal relationships. Identified as life-enabling competences, these are areas difficult to teach and not yet assessed, but critical to today’s society. This thesis calls for a paradigm shift in assessment thinking to bring about more innovative, holistic forms of assessment practice, which can support the learner’s sense of self and provide for sustainable lifelong learning. Peer- and self-assessment is shown to satisfy these criteria.