Objective To investigate whether work productivity in patients with spondyloarthritis (SpA) changed following the onset of the COVID-19 pandemic. Methods Data from the Dutch SpA-Net registry were used. Work productivity was assessed with the Work Productivity and Activity Impairment General Health questionnaire. Proportions of patients employed and their overall work impairment (0%–100%) were compared during a 1-year period before (‘pre-pandemic’) and a 1-year period after the onset (‘post-onset’) of the pandemic (March 2020). Generalised estimating equation analysis of all assessments since 2016 explored whether overall work impairment (absenteeism and presenteeism) in employed patients changed with pandemic onset, adjusting for confounders. Similar analyses with disease activity as outcome were used to facilitate interpretation of work productivity results. Results Data were available during pre-pandemic and post-onset years for 204 patients. Pre-pandemic, 128 (62%) patients were employed. Post-onset, 7 (3.4%) had lost employment, while another 7 (3.4%) originally unemployed gained employment. Overall work impairment was worse following pandemic onset (37.0%) compared with pre-pandemic (27.0%) (p<0.01). Post-onset increase in overall work impairment was mainly observed in patients with lower education (B=9.57, 95% CI 5.63 to 13.51) and largely attributable to absenteeism (B=11.15, 95% CI 7.44 to 14.86). In patients with high education, no such increase was seen. Disease activity did not change with pandemic onset. Conclusions Work productivity worsened in patients with SpA after pandemic onset, especially in patients with lower education, while employment losses were limited and disease activity remained stable. Work support should be considered during the COVID-19 pandemic and thereafter for those vulnerable to adverse work outcome.