The Fort de Boncelles is one of twelve forts built as part of the Fortifications of Liège in the late 19th century in Belgium.

The Fort de Boncelles is located about 8.3 kilometres (5.2 mi) south of the center of Liège.

The fort forms an isosceles triangle whose base is 300 metres (980 ft) long and whose sides measure 235 metres (771 ft). A 6-metre (20 ft) deep by 8-metre (26 ft) ditch encircles the fort. The principal armament was concentrated in the central massif. The ditches were defended in enfilade by 57mm guns in casemates resembling counterscarp batteries, firing at shot traps at the other end of the ditch. It is one of the larger forts of Liège.

With the exception of the Fort de Loncin, the Belgian forts made little provision for the daily needs of their wartime garrisons, locating latrines, showers, kitchens and the morgue in the fort’s counterscarp, a location that would be untenable in combat. This would have profound effects on the forts’ ability to endure a long assault. The service areas were placed directly opposite the barracks, which opened into the ditch in the rear of the fort (i.e., in the face towards Liège), with lesser protection than the two “salient” sides^. The Brialmont forts placed a weaker side to the rear to allow for recapture by Belgian forces from the rear, and located the barracks and support facilities on this side, using the rear ditch for light and ventilation of living spaces. In combat heavy shellfire made the rear ditch untenable, and German forces were able to get between the forts and attack them from the rear.

The Brialmont forts were designed to be protected from shellfire equaling their heaviest guns: 21 cm. The top of the central massif used 4 metres (13 ft) of unreinforced concrete, while the caserne walls, judged to be less exposed, used 1.5 metres (4.9 ft). Under fire, the forts were damaged by 21 cm fire and could not withstand heavier artillery.

Today only the postern, central massif, air intake tower and two nearby bunkers remain. The site includes a memorial to the dead of World Wars I and II, and a small cemetery. A museum opened next to the fort at the end of 2012