Taking the multidimensionality of well-being as its foundational premise, this chapter moves beyond unidimensional conceptualizations to incorporate hedonic, eudaimonic, and social dimensions. Its central aim is to critically review theoretical frameworks, empirical evidence, and methodological advances in measuring well-being across diverse contexts. Section 3.1 examines the theoretical foundations and typologies of well-being, differentiating hedonic, eudaimonic, and social constructs and their integrative models. Section 3.2 expands into novel domains—social-relational well-being, contextualized well-being in work and spatial environments, and cultural folk models—highlighting contextual and cultural variations. Section 3.3 traces the evolution of measurement paradigms from self-report scales to ecological momentary assessment and objective behavioral and physiological indicators. Finally, Sect. 3.4 addresses validity challenges and emerging opportunities, including system-level modeling and GeoAI. The chapter underscores the necessity of culturally informed, technologically enhanced, and ethically grounded frameworks to advance the holistic and equitable measurement of well-being.