First Presbyterian Church is a historic Presbyterian church at 175 East Main Street in Smithtown, Suffolk County, New York. It was built in 1825 and the sanctuary is a rectangular, two story frame structure measuring 56 ft by 34 ft. It is sheathed in wood shingles and covered by a gable roof. It features an engaged, square tower surmounted by a tiered, balustraded belfry. The tower has a Palladian window at its second level. The church was added to the National Register of Historic Places in 1977.