OBJECTIVES: To assess self-reported work productivity in people with multiple sclerosis (MS) and relate this to use of injectable (interferons/glatiramer acetate), oral (fingolimod/dimethyl fumarate/teriflunomide) or infusible (natalizumab/alemtuzumab) disease-modifying therapies (DMTs). METHODS: Facebook users in the USA who searched for MS or visited MS-related Facebook pages were directed to a survey via an online advertisement (July–September 2015). A screening questionnaire restricted the survey to people who confirmed they had a specialist diagnosis of MS, ≥12 months’ disease history and commercial health insurance, and were aged 18–65 years. Questions covered demographic/clinical characteristics, employment status and work productivity (for employed participants, using the Work Productivity and Activity Impairment Questionnaire: MS version 2.1). RESULTS: The survey was completed by 651 people, most of whom received DMTs (injectable, 37.2%; oral, 31.3%; infusible, 11.1%; none, 20.4%). People using infusible DMTs were youngest, followed by those receiving oral, injectable and no DMTs (mean±SD years: 44.6±13.8; 48.2±10.7; 50.9±10.1; 52.7±8.7, respectively). The same pattern was seen for MS duration since first symptom (mean±SD years: 12.7±7.1; 13.7±6.4; 13.7±6.8; 15.2±6.5, respectively). A higher proportion of participants receiving infusible DMTs were employed compared with those receiving injectable, oral or no DMTs (43.1% [n=31]; 31.8% [n=77]; 31.4% [n=64]; 31.6% [n=42], respectively). Of those employed (n=214), participants using oral DMTs had missed fewest work hours owing to MS in the past 7 days (mean±SD hours: oral, 3.1±8.6; infusible, 15.0±21.0; injectable, 7.6±15.1; no DMT, 5.0±11.9) and reported the lowest effect of MS on work productivity (scored 0–10, low score=less effect, mean±SD: oral, 2.3±2.3; infusible, 2.3±2.3; injectable, 3.1±2.4; no DMT, 2.4±2.4). CONCLUSIONS: Social media surveys are a novel method for capturing patients’ experiences in the real world. These results indicate that the impact of MS on work productivity was lower in people receiving oral DMTs than those receiving other DMTs or no DMT.