In this study, we evaluated the presence of residual disease in patients with axial spondyloarthritis (axSpA) in remission/low disease activity (LDA) status. This cross-sectional post-hoc analysis of the QUASAR study involving 23 rheumatology centres across Italy included adults with axSpA classified according to the Assessment of SpondyloArthritis International Society criteria. Patients with inactive disease (score < 1.3) or at least LDA status (score < 2.1) at baseline visit according to Ankylosing Spondylitis Disease Activity Score were investigated to evaluate how residual disease activity impacts patients’ quality of life. They were assessed using the Ankylosing Spondylitis Quality of Life (ASQoL) and EuroQoL 5-Dimension 5-Level (EQ-5D-5L) questionnaires. This study included 480 patients with axSpA (mean age, 47.5 ± 12.9 years, 64% male). In total, 123 patients (25.6%) had inactive disease and 262 (54.6%) had at least LDA. Using the ASQoL, ranges of 10–25% and 20–40% of patients with inactive disease and with LDA status, respectively, experienced tiredness/fatigue. Despite being classified with inactive disease, 48.8% of patients reported light pain/discomfort according to the EQ-5D-5L, with 4.1% reporting moderate pain/discomfort, whereas 55.7% of patients with LDA reported light pain/discomfort and 13% had moderate pain/discomfort. Using the ASQoL questionnaire, in patients with at least LDA, a higher proportion of women compared with males and a higher proportion of patients > 48 years of age (vs. patients ≤ 48 years) experienced tiredness. In this post-hoc analysis, ≥25% of axSpA patients in remission/LDA status were still burdened by residual disease, mainly characterised by pain and fatigue.