Forest & Bird (Māori: Te Reo o te Taiao), also known by its formal name as the Royal Forest and Bird Protection Society of New Zealand, is an environmental organisation specialising in the protection and conservation of New Zealand's indigenous flora and fauna and unique wild places and natural ecosystems. Forest & Bird consists of 47 branches located in urban and rural centres throughout New Zealand. Branches are actively engaged in conservation projects and advocacy on a community, regional and national basis. Forest & Bird has offices and staff located in Auckland, Christchurch, Wellington, Nelson and Dunedin. Forest & Bird publishes a quarterly magazine Forest & Bird, one of New Zealand's definitive natural history and conservation publications.

Forest & Bird has published a comprehensive commentary book on environmental law in New Zealand. Forest & Bird are also actively engaged in advocating and lobbying for resource management law and practices to more consistently protect ecosystems.

Forest & Bird was founded as the Native Bird Protection Society in 1923. Later renamed as the Royal Forest and Bird Protection Society of New Zealand, it has consistently advocated conservation issues, particularly for forested land.

Val Sanderson is acknowledged as the founder of Forest & Bird. In 1921, after his return from the First World War, the then Captain Val Sanderson was angered that the Kapiti Island wildlife reserve was unfenced and extensively damaged by cattle, sheep and goats. Sanderson campaigned for better management of Kapiti Island and succeeded in having it re-dedicated as a Wildlife Reserve. After this success, Sanderson held a public meeting in March 1923 which established the Native Bird Protection Society with Sir Thomas Mackenzie as the Society's first President. The New Zealand Forestry League, a forest conservation group already existed but it gradually died out. In 1935 Mackenzie and Sanderson renamed the society the Forest and Bird Protection Society of New Zealand. Sanderson drove an expansion of the society's range of interests into such areas as soil erosion and use of native trees for soil stabilisation. He became the president in 1933 a position which he held until his death in 1945 aged 79.

Until the 1970s, the Royal Forest and Bird Protection Society remained the only New Zealand environmental group. However, in October 1971 the New Zealand Government proposed to harvest large areas of native South Island lowland beech forest with half the cleared area to be converted to exotic Pinus radiata. Along with the Save Manapouri campaign, the native forest harvesting prompted more public awareness of conservation and the formation of new environmental groups such as the Beech Forest Action Committee. In response to the native forest harvesting, on 4 July 1975 Forest & Bird and Beech Forest Action Committee started the Maruia Declaration as a public petition demanding an end to native forest logging and legal recognition of native forests. The Maruia Declaration was submitted to the New Zealand Government in 1977.

From 2005 the society has held an annual poll Bird of the Year, voted on by the public. Winners to date include the kākāpō, the tūī and the New Zealand long-tailed bat.

In 2021, all proceeds from Lorde's Te Ao Mārama EP went to Forest & Bird as well as the Te Hua Kawariki Charitable Trust.

In April 2022, Nicola Toki took over from Kevin Hague as Chief Executive of Forest & Bird.