Çeltikdere Church (Turkish Çeltikdere Kilise) is located near the village of Çeltikdere in Bolu Province. The ruins of this Middle Byzantine church were around the border of Paphlagonia, Bithynia, and Phrygia around 100 km northwest of Ankara (ancient Ankyra) and 43 km south Bolu (ancient Claudiopolis). The church is on the west bank of a stream running through a scenic canyon-like valley. A rock-cut cave complex is on the opposite side of the stream.

This Middle Byzantine church, whose identification and history are completely obscure, perhaps dates to the 11th century. At some point, it was converted into a mosque, and then abandoned in 1952. It has since fallen into ruin, though its plan is still clearly discerned. Its three apses, along with a corner of its narthex, are among its best-preserved features.

Çeltikdere Church had a simple cross-in-square plan, measuring around 13 by 8.5 meters. The naos was slightly wider than it was long. Its narthex had a barrel vault, which has partially survived. Its exterior masonry consists of alternating bands of red brick and a soft local dark grey stone. The use of brick is limited almost exclusively to the exterior and was not used in the vaulting. The central apse is faceted on the exterior, semi-circular on the interior, and has three tall, thin windows. It is flanked by two semi-circular apses, each with a single window. It had stepped pilasters on the lateral façades marking the internal spatial divisions. As was common in Anatolia, it lacked a clearly defined pastophoria, so the tripartite sanctuary must have extended across the eastern bays. Its dome, which is now completely missing, was perhaps around 2.6 meters in diameter. It is unclear whether it was supported either by four columns or piers. A system of wooden tie beams was employed in the interior; fragments of some of its original wooden pieces still survive.

It is difficult to put Çeltikdere Church in a historic context. The high quality of the church suggests the influence of Constantinople, though numerous architectural features suggest a distance from the influence of Constantinople. It has been compared with other churches in both Constantinople and Anatolia. One example is the Cappadocian church Çanlı Kilise in Aksaray, which belonged to a rock-cut settlement. There are also rock-cut cave complexes in the vicinity of Çeltikdere. However this does not make it clear if Çeltikdere Church was a part of a monastery or was simply an individual church.

One rock-cut cave complex is on the opposite side of the stream from Çeltikdere Church. It has a staircase that leads to five irregular rooms with flat ceilings. Doors and windows have a square backing for locks on the inside. A small cave chapel is located a short distance north. There is another cave settlement with churches on the slopes of the nearby mountain to the north.