This chapter synthesized existing literature on functional diversity and ecophysiological traits of high-altitude plants along elevational gradients in the Western Himalayas and similar mountainous regions. It discussed how environmental stressors, including temperature, precipitation, UV radiation, and nutrient availability, influenced plant adaptations across varying altitudes. Key topics included patterns of species richness and distribution, morpho-anatomical variations such as leaf thickness, stomatal density, and root architecture, and eco-physiological responses like photosynthetic efficiency, nutrient resorption, and biochemical changes involving antioxidants and osmoprotectants. The compilation also covered molecular mechanisms, including gene expression, hormonal signaling, and transcriptomic regulation under multifactorial stresses. Emphasis was placed on the role of phenotypic plasticity and genetic diversity in enabling plant survival and acclimatization to harsh alpine conditions. Overall, the chapter highlighted implications for ecosystem resilience, biodiversity conservation, and vegetation responses to ongoing climate change in these dynamic environments.