The Reformed Church in Romania is a Calvinist denomination and the largest Protestant church in Romania. The majority of its followers are of Hungarian ethnicity and Hungarian is the main church language. The large majority of the Church's parishes are in Transylvania; according to the 2021 census, 495,380 people or 2.6% of the total population belong to the Reformed Church. About 95% of the members were of Hungarian ethnicity.

Romania is a country located at the crossroads of Central, Eastern and Southeastern Europe. It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to the east, and the Black Sea to the southeast. It has a predominantly continental climate, and an area of 238,397 km2 (92,046 sq mi) with a population of 19 million people (2023). Romania is the twelfth-largest country in Europe and the sixth-most populous member state of the European Union. Its capital and largest city is Bucharest, followed by Cluj-Napoca, Iași, Timișoara, Constanța, Craiova, Brașov, and Galați.