A mechitza (Hebrew: מחיצה, partition or division, pl.: מחיצות, mechitzot) in Jewish Halakha is a partition, particularly one that is used to separate men and women.

The rationale for a partition dividing men and women is given in the Babylonian Talmud (Sukkah 51b, 52a). A divider in the form of a balcony was established in the Temple in Jerusalem for the occasion of the Simchat Beit Hasho'evah (Water Drawing Ceremony) on Sukkot, a time of great celebration and festivity. The divider was first established to preserve modesty and attention during this time.

Orthodox Judaism is divided on whether a synagogue mechitza represents binding law or a custom. During the middle portion of the 20th Century, there were a substantial number of synagogues which considered themselves Orthodox but did not have one. However, the Orthodox Union (OU), the main body of Modern Orthodox synagogues in the United States, adopted a policy of not accepting synagogues without mechitzos as new members, and strongly encouraging existing synagogues to adopt them. Men and women are generally not separated in most Conservative synagogues, although it is a permissible option within Conservative Judaism and some Conservative synagogues, particularly in Canada, have one or have separate seating for men and women without a physical partition. Reform and Reconstructionist Judaism, consistent with their view that traditional religious law is not mandatory in modern times and a more liberal interpretation of gender roles, do not use mechitzos in their synagogues.