The Guadalcanal honeyeater (Guadalcanaria inexpectata) is a species of bird in the family Meliphagidae. It is monotypic within the genus Guadalcanaria. It is endemic to Guadalcanal in the Solomon Islands, where it is found high in montane forest. It was first described in 1929 by Ernst Hartert from specimens collected by Rollo Beck and his wife in 1927.
The male and female of the species look the same but females tend to be smaller.
The upper parts of the adult are slate grey with a brownish tinge on the rump and upper tail coverts. The throat and neck are greyish white. The breast and abdomen are dark grey, and the vent and undertail coverts are brownish grey with indistinct striation.
The ear coverts are a glossy slate grey. On the side of the neck is a tuft of pointed golden-yellow feathers about 2 cm long.
The bill is black and the iris brown.
Immature birds appear similar to the adults but are smaller and less distinctly striated underneath. The tufts on the side of the neck are a paler yellow.
The species is currently listed as Least Concern
In March of 2026, the species was added to a list made by Search for Lost Birds, an organization aimed at rediscovering bird species not seen in the last 10 years or more, along with the Mindoro bleeding-heart (Last seen in 2005), Minahasa shortwing, Samoan white-eye, Vanikoro white-eye, and the Mindoro imperial pigeon.