Sleep is fundamental to health and well-being, with women consistently reporting greater sleep problems than men, yet scant sociological research has examined gender differences in sleep quality. This paper analyses (i) gender differences in sleep problems, and (ii) how marital status differences in sleep problems differ among women and men. In both cases, the relative contributions of socio-economic status (SES), smoking, worries, health and depression in explaining these gender and marital status differences are analysed. Logistic regression is used to analyse the British Psychiatric Morbidity Survey 2000, which interviewed 8578 men and women aged 16 to 74. Women reported significantly more sleep problems than men, as did the divorced and widowed compared with married respondents. Gender differences in sleep problems were halved following adjustment for socio-economic characteristics, suggesting that SES inequalities play a major part in accounting for gender differences. This study casts doubt on the primacy of physiological explanations underlying gender differences in sleep. Marital status differences in sleep are greater among men than women, with previously partnered men reporting particularly poor quality sleep. However, this is largely explained by the more disadvantaged socio-economic circumstances of the previously partnered, especially for men. The paper concludes that gender and marital status differences are partly due to the lower socio-economic status of women and of the previously partnered.