ABSTRACT Purpose This study aimed to quantify the proportion of patients with bilateral epiphora and suspected nasolacrimal obstruction who self-reported improved epiphora bilaterally following unilateral dacryocystorhinostomy and investigate predictive factors. Methods A retrospective cohort study of patients from an Australian lacrimal clinic was performed. Eligible patients were at least 18 years of age, complained of bilateral epiphora, underwent unilateral dacryocystorhinostomy between 2012 and 2022 and followed-up. Outcome groups were created by grouping self-reported epiphora improvement levels for each eye. Two-sided confidence intervals were calculated for the proportion of participants in each outcome group. Ordinal elastic net regression identified clinical features associated with outcome groups and estimated their effect sizes. Results Of 243 patients, the median post-operative follow-up duration was 3 months. Fifty-eight percent (95% CI 52–64%, n = 141) reported significant improvement (≥50% ipsilateral and any contralateral improvement), 5% (95% CI 3–9%, n = 13) reported small improvement (<50% ipsilateral and any contralateral improvement) and 26% (95% CI 20–31%, n = 62) reported ipsilateral improvement only. Eleven percent had functional or anatomical failure. Older age (OR 1.01), contralateral nasolacrimal duct narrowing (OR 1.37), contralateral nasolacrimal duct obstruction (OR 0.93) and longer follow-up time (OR 0.85) predicted outcome groups. Conclusions After unilateral DCR, many patients with bilateral epiphora and suspected nasolacrimal obstruction report an improvement of their symptoms bilaterally in the early postoperative period. Contralateral nasolacrimal system diagnosis, patient age and follow-up duration were associated with outcomes. Further study using validated epiphora assessment tools may quantify this observation, and we suggest a potential underlying mechanism of contralateral effects after unilateral treatment.