Siddur Sim Shalom may refer to any siddur in a family of siddurim, Jewish prayerbooks, and related commentaries on these siddurim, published by the Rabbinical Assembly and the United Synagogue of Conservative Judaism. There are currently three versions of the Siddur Sim Shalom prayerbook, and two detailed commentaries that contain the entire text of the siddur. The commentaries are known as Or Hadash ("A New Light").