! In this chapter, we detail some of the main challenges of cross-cultural studies on well-being. We argue that these challenges revolve around underlying problems concerning the definition and assessment of well-being. Our specific focus is on three main challenges: (a) what to measure, (b) how to measure, and (c) the need for time- and cost-efficient measures. We argue that these challenges are relevant for an accurate analysis and understanding of cross-cultural differences in well-being. Finally, we describe the development of a new instrument designed to address some of the problems raised. The Pemberton Happiness Index, a brief measure of integrative well-being, taps into general, hedonic, eudaemonic, and social well-being and combines two methodologies to comprise both remembered and experienced well-being.