Oncidium, abbreviated as Onc. in the horticultural trade, is a genus that, as of December 2023, contains about 340 species of orchids from the subtribe Oncidiinae of the orchid family Orchidaceae. It is distributed across tropical and subtropical America from Mexico, Central America and the West Indies to northern Argentina, with one species (O. ensatum) extending into Florida. Common names for plants in this genus include dancing-lady orchid and golden shower orchid.

Orchids are plants that belong to the family Orchidaceae, a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Orchids are cosmopolitan plants that are found in almost every habitat on Earth except glaciers. The world's richest diversity of orchid genera and species is found in the tropics.