盛世广告（英语：Saatchi & Saatchi），中国和台湾译为上奇广告，香港译名为盛世广告，是全球第四大广告传播集团阳狮的子公司，由萨奇兄弟创办，总部设在英国伦敦。其与中国长城航空航天工业局的合资公司盛世长城成为中国最大的广告公司。其广告一直都以高格调而见称。

现时Saatchi兄弟因为与其他股东意见不合，所以已离开公司，并另组M&C Saatchi公司。萨奇兄弟的兄长莫里士·萨奇亦是英国保守党的前任主席之一。

Saatchi & Saatchi is a global communications and advertising agency network with 140 offices in 76 countries and over 6,500 staff. It was founded in London in 1970 but is now headquartered in New York. The parent company of the agency group was known as Saatchi & Saatchi PLC from 1976 to 1994, was listed on the New York Stock Exchange until 2000 and for a time, was a constituent of the FTSE 100 Index. In 2000, the group was acquired by the Publicis Groupe. In 2005 it went private.