Rhaeboctesis exilis is a species of spider in the family Liocranidae. It is endemic to South Africa and is commonly known as the Mussina rhaeboctesis sac spider.
Rhaeboctesis exilis is found in three provinces of South Africa, KwaZulu-Natal, Limpopo, and Mpumalanga. Notable locations include Ndumo Game Reserve, Kruger National Park, various nature reserves in the Limpopo Province, and the Lowveld National Botanical Garden.
The species inhabits Indian Ocean Coastal Belt and Savanna biomes at altitudes ranging from 47 to 1,523 m above sea level. These are free-running ground spiders that are rarely encountered.
Rhaeboctesis exilis is listed as Least Concern due to its wide geographical range. The species is known from eight protected areas, and threats to this species are not considered significant.
The species was originally described by Tucker in 1920 from Mussina (now Musina) in the Limpopo Province. The genus remains unrevised.