The Islamic religion has always placed great importance on water. Therefore, building a water structure such as a fountain, sebil or a sadirvan has always been an important charitable deed, and fountains constitute the most common group. Fountains, exclusively charity works built inside settlements as generally independent structures, can be divided into groups like sadirvan fountains, column fountains, wall fountains, freestanding fountains, pit fountains, window fountains and fork fountains. They were built for charity to provide water for a district or street, or for mosque communities as part of a social complex. It is known that approximately 125 fountains were built in Edirne, which was the capital of the Ottoman Empire for a long period. The wall fountain of the Selimiye Complex is not among the currently nonextant or unused fountains. This paper examines the wall fountain of the Edirne Selimiye Complex, which was built by an anonymous architect at an unknown date, does not have an inscription nor is mentioned in the biographies and pious endowment charters of Sinan the Architect or in the Selimiye Booklet by Dayezâde Mustafa Efendi. The study shows that the complex has been extensively analyzed in terms of its layout, architectural characteristics and decorations, whereas the fountain has never been studied. This paper introduces the fountain on the northern outer court wall of the complex for the first time in terms of its architectural characteristics and examines it in terms of location, construction and period. The paper also discusses the importance of the fountain among the relatively unknown ones built by Sinan, and evaluates it within the context of fountains and fountain architecture in Edirne. The Edirne Selimiye Mosque, Sinan’s masterpiece, was built on the old palace grounds (Saray-ıAtik) on a ridge called Kavak Meydanı. The structure, built by Sultan Selim II in 1568-1574, constitutes a small social complex. Buildings making up the complex are located inside a large, rectangular courtyard, and the mosque consists of a darülhadis medrese (hadith school) in the southeast, a darülkurra medrese (Quran school) in the southwest, and a row of shops, a time setter house and a primary school in the west. The shops bound the complex, which is surrounded by walls on three sides around the mosque and outer courtyard. The fountain on the northern outer courtyard wall is one-sided, approximately 140×120 centimeters in size. Shaped as a shallow niche on the wall, the fountain has a cusped quadricentric arch. The fountain, which has a 40-centimeter-wide inscription gap above the arch bears no inscriptions of repair or construction. The structure lacks an ornamental slab, and the shallow niche features a spout with a cascaded and multifoil arch. This section, currently filled with cement, is shaped like a bowl seat, and the vat stone was seemingly replaced. On both sides ring holes are visible, which probably had chains attached to drinking bowls. In certain examples, these are used as clips to fix the tap. A plastic pipe, presumably connecting the fountain to a water outlet, is visible between the paving stones. The simple wall fountain has no reservoir. The women’s bathroom is located behind the structure. It is thought that water was supplied from the same water line, or the old Palace bathhouse, for the fountain and bathroom. It appears that Sinan generally integrated such water structures into complexes on courtyard walls instead of freestanding fountains. Wall fountains are frequently seen in Sinan’s designs before and after Selimiye, like in Istanbul Suleymaniye Mosque (1550-1557), Silivrikapı Hadım İbrahim Pasha Mosque (1551), Kadirga Sokollu Mehmet Pasha Mosque (1567-1572), Üsküdar Atik Valide Mosque (1571-1584), Yedikule Haci Evhad Mosque (1585), and Fatih Mesih Mehmed Pasha Mosque (1584- 1586). Analogs of the fountain designed as a shallow niche on the courtyard wall were used by Sinan on sebil fountains on both sides of the gate inside the Selimiye Mosque. Like these structures, known as vat fountains, the upper section of the fountain’s vat – the base of the niche - is believed to be shaped like a circular bench. Fountains of this type stand in the legs of central gate on the outer courtyard wall of the Sultanahmet Mosque, facing the courtyard. Design similarities with the Selimiye fountain manifest in the master-apprentice relationship between Sedefkâr Mehmed Agha and Sinan in an architectural expression in the Sultanahmet Complex. Fountains generally have inscriptions above their ornaments or arches, seen as stone or marble slabs with inscriptions of the builder’s name, construction date, and Quran verses and hadiths about water as a masthead. In conclusion, the unknown and previously unstudied wall fountain shows that the Edirne Selimiye Complex had another water structure along with a sadirvan, ablution taps, sebil fountains inside both sides of the entrance, and the octagonal pool under the muezzin’s platform. It is presumed that this fountain, unmentioned in the biographies and pious endowment charters of Sinan like his many other fountains, was arranged as a sebil fountain on the northern outer courtyard walls. This structure, presumably designed by Sinan, was possibly completed after the mosque along with outer courtyard walls and the spolia column.