The church has a rectangular nave and chancel, with a bellcote of 1839 above the W gable. There are square traceried windows on the S side, and the E wall has been rebuilt, but otherwise the whole is substantially 12thc. The church is built in local sandstone and stands in a large churchyard overlooking suburban Leeds on one side and fields and woodland on the other.

Romanesque sculpture is concentrated in the S doorway, the corbel tables to N and S and on the chancel arch, but there are also decorated window heads and an unusual array of corbel-like heads on the W gable. The remains of a plain font are near the SW gate. The top of a pillar piscina, which had been re-set outside the chancel doorway, was stolen in 2002.

Roman remains have been found in the area. There may have been a pre-Conquest stone church (Draper, 1908). The Domesday Survey does not mention a church at Adel. Adel was held by Alweard in 1066. The manor was granted to Robert, count of Mortain, by William I. It was subinfeudated to Richard de Surdeval. Ralph Paganel or Paynel married one of Richard's daughters, who inherited it. Paynel had Holy Trinity church in York, which he re-established as a cell of Marmoutier, endowing it with the 'church of St John of Adela'. One carucate (of 1½ carucates in the territory of Adel) and the tithes of the desmesne were also granted by Ralph Paynel to Holy Trinity Priory. The present church was dedicated between 1152 and 1185 (Zarnecki, 1979). Sometime later, William Mustel gave the advowson of Adel church to Kirkstall. It is possible that there were two churches at Adel (Lancaster, 1895, 272-73). In 1166 the other half carucate of land at Adel was held by a knight, Robert d'Autrey, from William Paynel of Hooton Pagnell. Before 1204 it was gifted to Kirkstall Abbey (Faull and Moorhouse, 1981).

Regarding S doorway of the nave Whitaker (1816, 176) says that the porch, that is, the projection containing the S doorway, is separate fabric from the nave wall. He says that it is not much later, and it 'is so applied to the wall as plainly not to constitute part of the original plan; nor is the stone of the same kind.' Lewthwaite disagreed with this opinion. Draper (1908, 22) assumes the projection is the same or approximately the same age as the church, quotes architects and notes the apex cuts into corbel table; its capitals were comparable to those on the chancel arch (his judgment on this last point is not sufficient). It can be seen that the projection is coursed with the nave wall up to, or a little below, its own stringcourse, that is, to about 2.2m above ground level. Above that it is not coursed with the nave wall. This might account for the different opinions expressed as to coursing. The possibility therefore exists that there were two phases in construction of the S entrance in the 12thc. One phase could have provided the doorway of five orders, and a later work could have enlarged and embellished its gable with the apocalyptic subject, necessitating taking down some of the earlier work to key in the new work. These two phases might explain the duplication of evangelist symbols, which Whitaker describes; these are said to have been on capitals as well as the gable. Such duplication (assuming Whitaker identified the carvings correctly) would be unlikely if everything we now see had been built at one time. Two types of stone might well have been used in any case, one for the blocks in the lower parts and another suitable for the flat panels in the gable. The carving of flat panels in sandstone is reminiscent of work at Boroughbridge, found in the walls of the demolished St James' church and now re-set in the vestry of the parish church (see Boroughbridge site report). Frames are used around figures at Barton-le-Street (North Riding) and Healaugh (West Riding). For subject in gable, the Second Coming, compare version at Healaugh, S doorway. There is speculation about the flower-like decorations in the spandrels at Adel - numerous suggestions have been made, but shooting or falling stars would fit the Second Coming quite well. The Jouarre tomb of Bishop Agilbert has very flower-like falling stars in a similar composition. The only support for the plant idea is the base of the left spandrel, where a wavy shape could suggest ground on which a plant could stand, although there are no leaves anywhere, which one might reasonably expect. The wavy shape could represent cloud. For 19thc works, including restoration in 1879 by Street, see Draper (1908). The decorative effect does not preclude serious content, of course. Stillingfleet offers a comparison for the criss-crossed and berry-like balls of the 3rd order; Barton-le-Street for the Lamb carrying a pennant on the W gable.

As to the corbel table, the corbel table at Barton-le-Street (North Riding) is more complex even than this one, which itself is unusual. The pattern continues across the pilasters and all are coursed altogether. The corbel table is interrupted by the gable of the projection, as mentioned by Draper, but whether or not this would indicate that the gable was an afterthought I do not know.

Considering corbel NC8, the odd form of the necks can be compared to heads around an arch of the doorway at Salton (North Riding).

The chancel arch moulding on the second order and the strange motifs in many of the voussoirs in the third order are rather like carving that Deborah Kahn sees as the work of Normandy builders. Also with Norman connections is the pattern in the 2nd order. There are similarities in the chevron and label patterns used on the chancel arch and the doorway. However, the style of the sculpture on the chancel arch is somewhat different from that of the doorway (so far as we can judge), certainly from that in the gable. This change of style would not necessarily make the two parts of different date, as doorways seem often to have been made by separate craftsmen from the rest of the building.

Considering chancel arch capitals of the 1st order: compare N capital (Baptism of Christ), with an ivory casket of the Metz school, 9thc-10thc, which shows some of the same iconography. A baptism scene on a wooden door in Sant Maria im Kapitol, Cologne, dating from before 1065, shows water pouring itself from a vessel to the right of Christ, whose feet stand on the stream. To the left of his feet, the stream of water becomes a dog-like animal with its head turned upward. It is likely that the figure on the right is King David holding the shoot from the stem of Jesse. Isaiah 11:1,2 is a prophecy that associates the descent of the seven spirits of God (suitable for this baptism) with the shoot out of the root of Jesse, that is, Christ. It is possible that the crowned figure might symbolise the river Jordan, for this compare the mosaic in the dome of the Arian baptistery, Ravenna. In this mosaic, the classical personification of Jordan holds up a leafing branch but has two horns on his head. For the boar, compare an 8thc slab 'Exaltation of the Cross'. The rough cross in the scene of the Deposition represented on the S capital is unusual.

As to the capitals of the 3rd order, N capital (centaur) - compare Fishlake and Foston (North Riding). The centaur can (in these cases but not always elsewhere) be interpreted as Christ; the Agnus Dei fights a dragon at St Lawrence, York. Here at Adel he fights Death, and is presumably also irritated or tempted by Sin. A nice comparison is with the post-Conquest Tiberius Psalter, B.L. Cotton Tib.C.vi, fol. 14r., the Harrowing of Hell, where there is a little snarling dragon at the feet of Christ.

Musician in the 3rd order of the chancel arch (motif no. 18) is comparable to a corbel at Kirkburn (East Riding) on N side of nave. There are also figures standing within 'boxes' in the corbels at Kirkburn.

With regard to the carving of two beakheads on the E face of the chancel arch, Pevsner (1959, 339), says: 'This detail is a noteworthy proof of the fact that such sculptural decoration was done in situ or aprés la pose.' Even if this were the conclusion to be drawn in this instance, it certainly would not have been possible or practical to work like that generally.