AbstractObjectiveThis systematic review and meta‐analysis aimed to update the literature on orthorexia nervosa (ON), a proposed diagnosis of pathologically ‘healthy’ eating, by critically analysing the current evidence for the relationship between ON and obsessive‐compulsive (OC) symptoms. Further, this paper aimed to compare the ON/OC relationship significance and strength based on when the ON measurement tool was developed.MethodPsycINFO, PubMed and Web of Science databases were queried for quantitative, peer‐reviewed studies recruiting adult participants, published in English up to April 2023. Studies not directly comparing ON and OC symptoms were excluded. After full‐text review and quality assessment, 40 studies were included in the systematic review and 31 studies in the meta‐analysis.ResultsON assessments created prior to the 2016 revised ON diagnostic criteria do not appear to fully capture OC symptoms. Studies using earlier developed ON assessments demonstrated inconsistent ON/OC relationships whereas studies implementing more recent assessments (from 2018 onwards) found consistently significant, larger relationships, highlighting a previously underrated OC component of ON.ConclusionsEarly ON studies, and studies utilising early ON assessments should be interpreted with caution, particularly in relation to OC symptom involvement in ON. Future research should validate novel ON assessments and investigate common underlying factors.