Isaac Leeser (December 12, 1806 – February 1, 1868) was an American, Ashkenazi Jewish religious leader, teacher, scholar and publisher. He helped found the Jewish press of America, produced the first Jewish translation of the Bible into English, and helped organize various social and educational organizations. He is considered one of the most important nineteenth century American Jewish personalities. He was "fiercely opposed" to Reform Judaism and was regarded as one of the most important "orthodox" rabbis of his era. Leeser is regarded as a forerunner by both Modern Orthodox Judaism and Conservative Judaism.