Many isolated findings suggest that single parents report, on average, lower levels of happiness than others. These others, however, are not a single homogeneous group, and definitions vary according to the specific research question. Consequently, the picture of single parents’ happiness is still scattered. Drawing on the World Database of Happiness, we review systematically described research findings in a standardised manner, aiming to provide an overview of the association between single parenthood and happiness. Conclusions are based on findings from 54 publications, which analysed quantitative data and are spread over most countries of the Global North, covering the period from 1972 to 2020. This literature review shows that in nearly all countries covered, independent of historical time and irrespective of different definitions of single parenthood, single parents are, on average, less happy than other parents but, in certain conditions, happier than other individuals living without a partner. Various forms of informal support, employment, and the use of childcare are positively associated with single parents’ happiness. The review also reveals that single fathers are still not the focus of happiness research, nor are macro-level associations with single parents’ happiness.