Martinskirche, Protestant church in Bad Ems, Germany.

Martinskirche is a Protestant church building in the spa town of Bad Ems located beside the Lahn River. Its masonry and proportions reflect regional construction principles that have been rooted in Rhineland-Palatinate for centuries.

Around 1000 the church belonged to the St. Kastor monastery in Koblenz, and a parish existed by 1181. The Romanesque pillar basilica was probably built in the middle or third quarter of the 12th century, following the church of Niederlahnstein. After a fire in 1720 it was restored, and it was restored again in 1957.

The church serves Bad Ems's Protestant community as a gathering place for worship and anchors the town's spiritual identity. It stands within a town that developed as an exclusive retreat for nobility and affluent visitors, offering a quiet counterpoint to the therapeutic bustle of the thermal springs.

The church stands in Bad Ems, a short walk from the thermal baths and the paths along the Lahn. The south side opens through a plain round-arched stepped portal with a blind arch. The building is used for regular services, so opening times vary with events and worship.

The two small east windows above the choir roof are the only original Romanesque windows left; the upper clerestory windows were enlarged in the 18th century and reduced again in 1957. The organ is a 2014 work by Eule Orgelbau of Bautzen with 18 stops on two manuals and pedal.