Developmental idealism (DI) is a system of beliefs and values that endorses modern societies and families and sees them as occurring together, with modern families as causes and consequences of societal development. This study was motivated by the belief that the population of Nepal has absorbed these ideas and that the ideas affect their family behaviour. We use data collected in Nepal in 2003 to show that Nepalis discuss ideas about development and its relationship to family life and that DI has been widely accepted. It is related in predictable ways to education, paid employment, rural?urban residence, and mass media exposure. Although it would be useful to know its influence on demographic decision-making and behaviour, we cannot evaluate this with our one-time cross-sectional survey. Our data and theory suggest that this influence may be substantial.; Developmental idealism (DI) is a system of beliefs and values that endorses modern societies and families and sees them as occurring together, with modern families as causes and consequences of societal development. This study was motivated by the belief that the population of Nepal has absorbed these ideas and that the ideas affect their family behaviour. We use data collected in Nepal in 2003 to show that Nepalis discuss ideas about development and its relationship to family life and that DI has been widely accepted. It is related in predictable ways to education, paid employment, rural?urban residence, and mass media exposure. Although it would be useful to know its influence on demographic decision-making and behaviour, we cannot evaluate this with our one-time cross-sectional survey. Our data and theory suggest that this influence may be substantial.