The study of niches in the interiors of medieval dwelling houses of Ani, the largest Christian city in Armenia, carries out for the first time as part of a monographic article. The material for the study is the samples of niches in the structure of the houses of Ani excavated by the expedition of Nikolay Marr more than a century ago and by Turkish archaeologists over the past decades. The typological classification, carried out according to various criteria, contributes to the ordering of this material, which, despite its wide popularity, turned out to be poorly studied. Special attention is paid to the conches of the niches, which often had sculptural and carved decoration. It made the niche the most expressive form in the entire room. The dating of the studied niches within the epoch between the second half of the 12th and the first half of the 14th century is confirmed by the peculiarities of the stylistic implementation of these architectural forms, as well as their visual similarity with the niches created in the apses of Armenian churches, starting from the turn of the 12th–13th centuries. Reflections are expressed on the purpose of niches in the halls of dwelling houses, some palaces, on their similarity to the niches depicted in the miniatures of manuscripts, with the titles of the gospels. The similarity with the niches in the palaces of the Seljuks of Asia Minor also is detected.