Objective To assess in patients with ankylosing spondylitis (AS) whether extra-articular manifestations (EAMs) are associated with worse functioning, worse quality of life (QoL), and more radiographic damage over time. Methods 12-year follow-up data from the Outcome in Ankylosing Spondylitis International Study were used, complemented with data on EAMs extracted from medical charts. Functioning was assessed by the BASFI and physical component of the SF-36, QoL by ASQoL and EuroQoL, and radiographic damage by the mSASSS. Generalised estimating equations analyses were made to assess whether EAMs were associated with these outcomes over time. Results 216 patients were included (154 (71%) men, mean age 43.6 years (SD 12.7), mean symptom duration 20.5 years (SD 11.7), and mean follow-up 8.3 years (SD 4.3). In total, 58 (26.9%) patients had acute anterior uveitis (AAU), 24 (11.1%) inflammatory bowel disease (IBD), and 14 (6.5%) psoriasis. Univariably, IBD was associated with worse BASFI over time (B=1.26, 95%-CI 0.13 to 2.39, p=0.03), but not in a multivariable model. Furthermore, in a multivariable model, IBD was associated with EuroQoL over time (B=2.93, 95%-CI 0.14 to 5.72, p=0.04). Univariably, psoriasis was associated with radiographic damage (B=-7.25, 95%-CI -14.38 to -0.12, p=0.05) and ASQoL (B= -1.94, 95%-CI -3.32 to -0.57, p