Between 1850 and 1950, three shifts occurred in Britain: an increase in the proportion of one-child families, the related growth of negative stereotypes relating to only children, and the addition of new, negative meanings to the word ‘lonely’. One emergent perception of only children was that they experienced loneliness, and they were therefore unhappy. This essay shows that whether an individual only child growing up in this period reported loneliness depended on a number of factors, including their personality, geographical location, class and gender. It also shows that the word ‘lonely’ retained its neutral sense in everyday use throughout the 20th century, challenging the idea that there was a clear and unambiguous shift in its meaning.