This article aims to assess happiness among young people aged 18–29 years in 2009 and 2014, using a multidimensional Happiness Index among Youth (HIY), based on the Survey of Young People in Egypt (SYPE). Uncertainty and sensitivity analysis are applied to examine the robustness and efficiency of the index. A multinomial model is used to study the main determinants of happiness among young people. The main results of the study are that young men are happier than young women. The educational level of the head of household has a positive, significant effect on happiness.