Introduction: The purpose of this study was to evaluate the within-pair difference in retinopathy of prematurity (ROP) between donors and recipients with twin-to-twin transfusion syndrome (TTTS) and to identify risk factors for ROP development. Methods: This retrospective cohort study included 147 TTTS twin pairs managed between 2002 and 2022 and eligible for ROP screening. Primary outcomes were any stage ROP and severe ROP. Secondary outcomes were hemoglobin at birth, red blood cell transfusions, mechanical ventilation days, postnatal steroids, and neonatal morbidity. Donor status was defined as having polyhydramnios pre-laser. Results: Rates of any stage ROP (23% vs. 14%) and severe ROP (8% vs. 3%) were significantly higher in donors compared to recipients. Donors received a higher number of blood transfusions (1 [±1.9] versus 0.7 [±1.5]). Five factors were univariately associated with any stage ROP: donor status (odds ratio [OR] 1.9; 95% CI 1.3–2.9), lower gestational age (GA) at birth (OR 1.7; 95% CI 1.4–2.1), small for GA (OR 2.1; 95% CI 1.3–3.5), mechanical ventilation days (OR 1.1; 95% CI 1.1–1.2), and blood transfusions in phase 1 (OR 2.3; 95% CI 1.2–4.3). Three factors were independently associated with any stage ROP: donor status (OR 1.8; 95% CI 1.1–2.9), lower GA at birth (OR 1.6; 95% CI 1.2–2.1), and mechanical ventilation days (OR 1.1, 95% CI 1.0–1.1). Donor status was univariately associated with severe ROP (OR 2.3, 95% CI 1.1–5.0). Conclusion: Any stage ROP and severe ROP are detected twice as frequently in donors compared to recipients. Increased awareness for ROP is needed in donors, especially those with lower GA at birth and longer duration of mechanical ventilation.