Physical activity (PA) is associated with numerous health-related benefits among adults with chronic diseases and the general population. As the benefits are dose-dependent, this review aims to establish the PA levels of adults with spondyloarthritis and to compare these to the general population. Electronic databases (Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE/PubMed, PEDro, AMED, CINAHL) were systematically searched from inception to May 2014 using medical subject headings and keywords. This was supplemented by searching conference abstracts and hand-searching reference lists of included studies. Eligible studies were randomized controlled trials and observational studies of adults with SpA in which free-living PA or energy expenditure levels were measured. Subjects less than 18 years or with juvenile-onset SpA were excluded. Outcomes included objective and self-report measurements. Two reviewers independently screened studies for inclusion and assessed methodological quality using the Cochrane risk of bias tool and the RTI item bank. From the 2,431 records reviewed, nine studies involving 2,972 participants were included. This review focused on qualitative synthesis. Meta-analyses were not undertaken due to differences in study design, measurement tools, and participant characteristics. This heterogeneity, coupled with the risk of bias inherent in the included observational studies, limits the generalizability of findings. Objective measurements suggest PA levels may be lower among adults with spondyloarthritis than in healthy population controls. Self-reported PA and self-reported rates of adherence to PA recommendations varied largely across studies; higher disease activity was associated with lower self-reported PA levels. Physical activity levels may be lower in adults with axial spondyloarthritis, with higher disease activity associated with lower PA levels.