Sundrang, a customary prestation given by the groom's side to the bride's family before the marriage contract, remains an important expression of respect and family identity among the Bugis-Makassar community in Masalembu. This study examines the authority of the bride's family in determining Sundrang and the limits of that authority when the prestation becomes connected to the guardian's consent. Using a qualitative, normative-sociological case-study approach, the study draws on interviews with twelve purposively selected informants in Masalima Village, Masalembu. The findings show that Sundrang is distinct from mahr and is determined through family deliberation, but a socially circulating benchmark of approximately IDR 20–30 million increasingly influences expectations. Under Bugis-Makassar customary law, the bride's family has a legitimate role in determining Sundrang insofar as the practice serves the customary purposes associated with Pangadareng and Siri'. That authority becomes difficult to justify when Sundrang functions primarily as a prestige measure, causes substantial economic pressure, postpones or prevents a marriage, or is used as an indirect means of refusal. From the perspective of fiqh al-munakahat, Sundrang is not a requirement for the validity of marriage. Accordingly, a guardian's withholding of consent solely because Sundrang has not been fulfilled, absent another recognised Islamic ground for refusal, may substantively fall within the concept of wali adhal; any formal transfer of guardianship to a wali hakim remains subject to the procedure prescribed by Indonesian law. The study concludes that the continuity of Sundrang depends on maintaining its customary function without turning it into an independent condition for marriage or guardian consent.