The Downtown Triangle (Hebrew: המשולש, Ha-Meshulash, lit. "The Triangle"; Arabic: مثلث وسط المدينة) is a commercial and entertainment district in central Jerusalem. Measuring 29,000 square metres (310,000 sq ft), the area is bounded by Jaffa Road on the north, King George Street on the west, and Ben Yehuda Street on the southeast. Its vertices are the intersections of Jaffa Road and King George Street, King George and Ben Yehuda Streets, and Ben Yehuda Street and Jaffa Road (the latter known as Zion Square).

From the mid-1940s through the 1960s, the Triangle was the commercial and cultural heart of Jerusalem, with many upscale shops and restaurants operated by German-Jewish immigrant businessmen that appealed to an affluent clientele. Following the reunification of Jerusalem in 1967 and the expansion of the city away from the downtown core, the commercial viability of the Triangle declined. The area was revitalized by the conversion of Ben Yehuda Street and the interior streets of the Triangle to an open-air pedestrian mall in 1982. Over the next two decades, outdoor cafes and souvenir shops moved in, cementing the reputation of the Triangle as a popular shopping and entertainment venue for tourists and young Israelis.

Before the British Mandatory government took over in 1917, the main commercial district in Jerusalem was in the Old City. With an eye to the continuing development of new neighborhoods outside the Old City Walls, the British drew up a master town plan that called for the establishment of two commercial hubs in the New City. The first commercial district to be built was the Downtown Triangle, although it was intended to play a secondary role to the other planned commercial district in the Mamilla area, which was closer to the Old City. However, the Mamilla development did not garner as much interest as the Triangle.

The land used for the Downtown Triangle had been purchased by the Jewish Colonization Association from the Greek Orthodox Patriarchate, which began selling off some of its holdings in Jerusalem after World War I. The British developed the field into a triangular district (hence its appellation, "The Triangle") demarcated by Jaffa Road, Ben Yehuda Street (constructed by the British in 1922) and King George Street (constructed by the British in 1924). Lots were sold to large companies and cooperatives as well as private businesses. Other streets adjacent to the Triangle – Shlomzion Hamalka, Mamilla, Agron, and King David Streets – were zoned for commercial and residential use.

According to Jerusalem architectural historian David Kroyanker, the heyday of the Downtown Triangle lasted from the early 1930s to the 1970s. Many stores and restaurants were opened by German Jewish immigrants who sought to recreate a European ambience in the city center. Their upscale boutiques, coffeehouses, delicatessens, and exclusive restaurants were frequented by senior Mandate officials and wealthy, English-speaking tourists. Unlike Israeli stores that sold all kinds of unrelated products under one roof, the Europeans introduced boutiques that featured only one item, such as gloves or ties. Some shops offered unique extras, such as coffeehouses that included an orchestra and dance floor, and a bookstore with a second-floor library.

The European immigrant-owned bookstores fueled the demand for detective fiction, historical reading, and periodicals from Germany and England. Steimatzky, which opened its first bookstore on Jaffa Road in the Triangle in 1925, identified the growing taste for imported newspapers and magazines and bought the franchises for many of them. The European immigrants also created a market for cold cuts and cheeses, with three competing delicatessens on King George and Ben Yehuda Streets. For many years, the Triangle was also the only place where Jerusalem residents could purchase clothing, shoes, furniture, and household goods.

At its peak, the district was home to 14 cinemas screening the newest Hollywood fare. Located in close proximity to one another, the cinemas would attract both adults and youth, who would afterwards patronize the coffeehouses and restaurants. The Downtown Triangle was the cultural heart of the city and the place "to see and be seen".

The cosmopolitan flavor of the Triangle extended to its buildings. The Sansur building, for example, has an "eclectic" design that combines "neo-Renaissance and classicist elements". Approximately 15 buildings in the Triangle were designed by architect Reuven Avraham Rabinowitz, who often added a row of roughly dressed stone to the facade to demarcate each story.