It is increasingly common for respondents to complete web surveys using mobile devices (smartphones and tablets) rather than personal computers/laptops (PCs). Evidence of the impact of the use of mobile devices on response and data quality shows mixed results and is only available for general population surveys. We looked at response quality for a work-related survey in the UK among general practitioners (GPs). GPs were sent email invitations to complete a web survey and half (55%) completed it on a mobile device. While GPs using a mobile device were less likely to complete the full questionnaire than those using a PC, we found no differences in data quality between mobile and PC users, except for PC users being more likely to respond to open-ended questions.