The Reformed Church of Olosig (Biserica Reformată Olosig) is a Calvinist church next to Liberty Park in Oradea, Bihor County.
The church was constructed in a Classicist and Baroque style between 1784 and 1787 following the plans of the architect Iacob Eder. In 1884, the church underwent a restoration and transformation under the supervision of the renowned architect Kálmán Rimanócczy Sr.
