This study evaluated changes in oral glucocorticoid (GC, prednisone equivalent) use among patients with generalized myasthenia gravis (gMG) previously using chronic GCs, who initiated and continued efgartigimod for ≥12 months, identified retrospectively from a US claims database. Myasthenia Gravis Activities of Daily Living (MG-ADL) scores were retrieved from a patient support program. The primary outcome was GC average daily dose (GC ADD) assessed during the 3 months before and 3, 6, 9, and 12 months after efgartigimod initiation. Overall, 266 patients were included (mean age: 59.8 years; 45 % female). Mean (95 % CI) GC ADD was significantly reduced at 3 (14.3 [12.6, 16.0] mg/day), 6 (13.4 [11.5, 15.4] mg/day), 9 (11.6 [10.0, 13.3] mg/day), and 12 (10.2 [8.8, 11.6] mg/day) months post-efgartigimod initiation compared to baseline (17.9 [15.7, 20.1] mg/day) (p < 0.001). At 12 months, 66 % (n = 176/266) reduced steroid dose. Among those, 68 % and 51 % achieved ≥50 % and ≥ 75 % ADD reduction, respectively. The proportion of patients using GC ADD of ≤5 mg/day increased from 13 % at baseline to 42 % at 12 months. Among 126 patients (47 %) who had MG-ADL scores available, there was a significant reduction from baseline in best follow-up mean (95 % CI) MG-ADL (from 7.9 [7.2, 8.5] to 3.1 [2.6, 3.6]), while mean GC ADD remained significantly reduced (p < 0.05). Thus, in patients with gMG using chronic GCs at baseline, GC use substantially reduced following efgartigimod initiation, while retaining improved MG-ADL scores, underscoring the potential steroid-sparing effect of efgartigimod in gMG treatment.