Siddur Sim Shalom is the iconic series of Conservative / Masorti siddurim, published jointly by the Rabbinical Assembly and the United Synagogue of Conservative Judaism.

The original Siddur Sim Shalom, edited by Rabbi Jules harlow z”l and published in 1985, was the first comprehensive siddur published by and for the Conservative / Masorti Movement. The Sim Shalom series features the innovative prayers and remarkable translations from the original edition, and now includes six subsequent additions to the series, including separate Shabbat and Festivals and Weekday siddurim, personal and travel sized editions, an adapted transliterated version of the Friday night service, and two volumes of commentary.

Siddur Sim Shalom is a staple in the Conservative / Masorti Movement, found in nearly every synagogue, school, and summer camp.