Children’s material living standards determine a wide range of short- and long-term outcomes, including health, educational attainment, and social and emotional functioning. This chapter discusses the distinction between children’s material living standards and related concepts and presents some of the methods by which children’s material deprivation can be operationalized. We argue that the use of child-specific indicators of material living conditions, in addition to household-level measures, presents the most direct way of capturing the actual living conditions children experience. Problems inherent in the use of other measures, particularly income, can be avoided using these measures. In addition, the separation of material living standards from other aspects of poverty facilitates a better understanding of some of the mechanisms through which material deprivation and other facets of poverty and/or deprivation interact to affect well-being in both childhood and adulthood.