The Rodrigues solitaire (Pezophaps solitaria) is an extinct flightless bird that was endemic to the island of Rodrigues, east of Madagascar in the Indian Ocean. A member of the family of pigeons and doves, it was most closely related to the also extinct dodo of the nearby island Mauritius, the two forming the subfamily Raphinae. The Nicobar pigeon is their closest living genetic relative.

Rodrigues solitaires grew to the size of swans, and demonstrated pronounced sexual dimorphism. Males were much larger than females and measured up to 75.7–90 centimetres (30–35 inches) in height and 28 kilograms (62 pounds) in weight, contrasting with 63.8–70 centimetres (25–28 in) and 17 kilograms (37 lb) for females. Its plumage was grey and brown; the female was paler than the male. It had a black band at the base of its slightly hooked beak, and its neck and legs were long. Gizzard stones helped digest its food, which included fruit and seeds. Both sexes were highly territorial, with large bony knobs on their wings that were used in combat, probably due to competition for the limited resources on the island. The Rodrigues solitaire laid a single egg that was incubated in turn by both sexes.

First mentioned during the 17th century, the Rodrigues solitaire was described in detail by François Leguat, the leader of a group of French Huguenot refugees who were marooned on Rodrigues in 1691–1693. It was hunted by humans and introduced animals, and was extinct by the late 18th century. Apart from Leguat's account and drawing, and a few other contemporary descriptions, nothing was known about the bird until a few subfossil bones were found in a cave in 1786. Thousands of bones have subsequently been excavated. It is the only extinct bird with a former constellation named after it, Turdus Solitarius.

The French explorer François Leguat was the first to refer to the bird as the "solitaire" (referring to its solitary habits), but it has been suggested that he borrowed the name from a 1689 tract by his sponsor Marquis Henri Duquesne, which used the name "solitaire" in reference to the Réunion ibis. The bird was first scientifically named in 1789 as a species of dodo (Didus solitarius, based on Leguat's description) by the German naturalist Johann Friedrich Gmelin in the thirteenth edition of Systema Naturae. In 1786, subfossil Rodrigues solitaire bones encrusted in stalagmite were discovered in a cave on Rodrigues and sent to the French naturalist Georges Cuvier in about 1830. For unknown reasons, he stated they had recently been found on Mauritius, which caused confusion, until they were compared with other bones found on Rodrigues in 1831 that were shown to belong to the same, distinct species by the English naturalists Hugh Edwin Strickland and Alexander Gordon Melville in 1848. The latter bones were thought lost until they were rediscovered in 1852.

Strickland and Melville suggested the common descent of the Rodrigues solitaire and the dodo in their 1848 monograph about the latter. They dissected the only known dodo specimen with soft tissue, comparing it with the few Rodrigues solitaire remains then available. They stated that, although not identical, these birds shared many distinguishing features in the leg bones otherwise only known in pigeons. The fact that the Rodrigues solitaire laid only one egg, fed on fruits, was monogamous and cared for its nestlings also supported this relationship. Strickland recognised its generic distinction and named the new genus Pezophaps, from ancient Greek pezos (πεζός 'pedestrian') and phaps (φάψ 'pigeon'). The differences between the sexes of the bird were so large that Strickland thought they belonged to two species, naming the smaller female bird Pezophaps minor in 1852.

Additional subfossils were recovered during the 1860s, but more complete remains were found during the 1874 transit of Venus, since an observation station was located on the island. Many of these excavations were requested by the English ornithologists (and brothers) Alfred and Edward Newton, who used them to describe the osteology of the bird in detail. Thousands of bones were excavated, and mounted skeletons were composed from the remains of several specimens. Study of skeletal features by the Newtons indicated that the solitaire was morphologically intermediate between the dodo and ordinary pigeons, but differed from them in its unique carpal knob.

Some scientists believed that Réunion was home not only to a white dodo, but also to a white bird similar to the Rodrigues solitaire, both of which are now believed to be misinterpretations of old reports of the Réunion ibis. An atypical 17th-century description of a dodo and bones found on Rodrigues, now known to have belonged to the Rodrigues solitaire, led the British taxidermist Abraham Dee Bartlett to name a new species in 1851, Didus nazarenus; it is now a junior synonym of this species.

At one point it was suggested that the skeleton of this species is the best described after that of humans. In spite of the evidence, some later scholars doubted Leguat's story, and the existence of the Rodrigues solitaire. In 1921, the American linguist Geoffroy Atkinson claimed Leguat's memoir was merely a novel, and that the man had never even existed, and in 1955, the British ecologist George Evelyn Hutchinson doubted aspects of the bird's biology mentioned by Leguat. Today, it is widely accepted that Leguat's memoirs are credible observations of the bird in life.