Marigold (Tagetes spp.) is a valuable ornamental crop with aesthetic, commercial, and religious use value and is available in variable varieties, but its diversity in Nepal has not been recorded to date. In this study, 29 marigold landraces were used along with one commercial check variety. Marigold landraces were collected from four districts (Ilam, Jhapa, Morang, and Sunsari) of Nepal, and research was conducted at two locations, Ilam and Sunsari, to assess phenotypic variation in plant height, number of branches, flower diameter, petal number, days to flowering, and yield characteristics in various landraces. GGE biplots was used to rank mean performance and stability for vegetative architecture, floral quality, phenology, and yield. The first principal component explained the majority of G + GE pattern across traits, and hence rankings were reliable. Co16866 and Co16868 possessed stable good architecture with minimal instability. In flower traits, high and stable diameter and peduncle length entries suited cut-flower markets, and high petal number in combination with medium flower weight suited garland use. Phenology separated very clearly between sites: Ilam was earlier, Sunsari was later. Yield confirmed multi-trait signal, with Co16872, Co16859, Co16865, Co16884, and Co16871 being high-stable, and Co16869 low-stable. Commercial check Co16886 was above average but less stable than leaders. Right-side, near-axis entries are suggested to carry forward for broad release, pairing early-stable lines for Ilam with later-stable, longer-peduncle lines for Sunsari to product goals.