The Standard Prayer Book commonly known as Singer's Siddur is an English translation of the Hebrew siddur created by Rabbi Simeon Singer. A siddur is term for a Jewish prayer book, containing a set order of daily prayers. The word siddur comes from the Hebrew and means 'order'. Singer provides an authorized version of the liturgy capable of standardizing and stabilizing the synagogue service and helping to create an "established" Judaism. The author's goal was to unite precision and literalness regarding English language and the simplicity of expression suiting the religious prayer. Singer's Siddur has gone through many editions, and is still used in many synagogues and homes.

Simeon Singer (1846-1906) was an English Rabbi, preacher, lecturer and public worker. He is best known for his English translation of the Authorized Daily Prayer Book, informally known as the "Singer's Siddur".