Spontaneous singing is widely acknowledged as an important part of young children’s everyday musical experience. However, its fleeting and often private nature makes it difficult to study. Research into young children’s singing at home frequently relies on data gathered through parental reporting, and studies are often limited to small sample sizes. In this article, I explore the nature, extent and contexts of spontaneous singing among 15 three- and four-year-old children at home. Continuous audio recording was used to collect naturalistic data during the children’s normal everyday routines. This innovative method resulted in data that could be analysed quantitatively to provide a comprehensive overview of spontaneous singing in young children’s everyday home lives that has so far been missing from the literature. Analysis showed that all the children sang spontaneously. The singing behaviours they displayed were similar to those described in the literature, but contrary to some of the literature, the most prevalent singing behaviours were improvisatory. Spontaneous singing occurred during many everyday activities; however, the strongest influence on singing was found to be the social context in which it took place. The children used different ways of singing when interacting socially or when playing on their own, with most singing occurring when children were on their own, potentially unnoticed by adults.