Part-time work is widely considered functional for the economy, with both benign and detrimental implications for employees. However, specific analyses of involuntary part-timing in Britain are surprisingly absent from the flexibility debate; and workers in such positions remain largely under-researched. This article explores the relation of involuntary part-time work to demographic and work-related circumstances, hoping to provide a contribution to the examination of working patterns in the UK. We analyse Labour Force Survey data, using logistic regression modelling to identify the segments of workers filling part-time jobs involuntarily. The results suggest that being couple with dependant children considerably reduces the likelihood of involuntariness among female part-timers whereas it has an opposed effect on their male counterparts. Lower educational and occupational levels, on the other hand, imply a higher likelihood of involuntariness across both sexes