Digital technologies and artificial intelligence are transforming how teaching, learning, and assessment operate in online environments. As digital platforms, automated feedback systems, and AI tools become embedded in educational practice, long-standing assumptions about validity, academic integrity, and learner performance are being fundamentally re-examined. This timely volume addresses these shifts by offering a principled and forward-looking framework for digital assessment in online teaching and learning. Bringing together theoretical insight and practice-based innovation, the book explores construct-sensitive task design, AI-supported formative assessment, feedback literacy, scenario-based evaluation, and curriculum-level integration across diverse educational contexts. Rather than framing technology as a threat to assessment integrity, the contributors demonstrate how ethical design, professional judgment, and institutional coherence can ensure meaningful evaluation in digitally mediated environments. Combining conceptual depth with practical relevance, this volume is an essential resource for researchers, teacher educators, graduate students, and policymakers seeking sustainable, future-ready models of assessment for online education.