Due to the lack of treatment guidelines for the management of advanced-stage marginal zone lymphoma (MZL), only one chemoimmunotherapy-cyclophosphamide, vincristine, and prednisone plus rituximab (R-CVP)-is reimbursed in the first-line setting in South Korea. The aim of this study was to develop a consensus-based recommendation for the treatment of patients with advanced-stage MZL. Twelve hematologist oncologists participated in a two-round Delphi process to identify consensus on the management of patients with advanced-stage MZL in South Korea. Physicians rated their level of agreement with each statement on a four-point Likert scale. Statements were divided into two sections: definitions used in clinical practice and clinical management of patients with advanced-stage MZL. Consensus was reached for 23 of 33 (69.7%) and 5 of 13 statements (38.5%) in rounds 1 and 2, respectively. There was strong consensus (91.7%) that advanced-stage MZL subtypes are defined according to the Lugano staging system. First-line systemic treatment should be prescribed for patients with symptomatic advanced-stage MZL. Although there was unanimous agreement that R-CVP is the standard first-line treatment for advanced-stage MZL, physicians also agreed that bendamustine with rituximab (BR) has greater efficacy than R-CVP as first-line treatment (91.7%). For the treatment of relapsed/refractory advanced-stage MZL, BR and R-CVP can be repeated in patients with short (< 24 months) and long remission periods (≥ 24 months), respectively. This study provides insights on the management of patients with advanced-stage MZL in South Korea. This may enhance clinical decision-making, thus improving patient outcomes.