Background: Available data on mycophenolate mofetil (MMF), azathioprine (AZA) and methotrexate (MTX) for paediatric-onset anti-N-methyl-D-aspartate receptor encephalitis (anti-NMDARE) is limited. Methods: Systematic literature review on patients treated with MMF/AZA/MTX for paediatric-onset anti-NMDARE, with focus on modes of use, efficacy and safety. Results: 87 patients were included (age at onset median 11 years, range 0.8e18 years; 69% females). 46% had a relapsing course. 52% received MMF, 27% AZA, 15% MTX, and 6% a combination of MMF/AZA/MTX (7 patients received intrathecal MTX). Before MMF/AZA/ MTX, 100% patients received steroids, 83% intravenous immunoglobulin and 45% plasma exchange, and 50% received second-line treatments (rituximab/cyclophosphamide). MMF/ AZA/MTX were administered >6 months from onset in 51%, and only after relapse in 40%. Worst mRS before MMF/AZA/MTX was median 4.5 (range 3e5). At last follow-up (median 2 years, range 0.2e8.6), median mRS was 1 (range 0e6). Median annualised relapse rate was 0.4 (range 0e6.7) pre-MMF/AZA/MTX (excluding first events), and 0 on MMF/AZA/ MTX (mean 0.03, range 0e0.8). 7% patients relapsed on MMF/AZA/MTX. These relapsing patients had low rate of second-line treatments before MMF/AZA/MTX (25%), long median time between onset and MMF/AZA/MTX usage (18 months), and frequently they were started on MMF/AZA/MTX only after relapse (75%). Relapse rate was lower among patients who received first immune therapy 30 days (25%) than later (64%), who received second-line treatments at first event (14%) rather than