A Jewish community with a synagogue and cemetery existed in the early 14th century, and was destroyed in the Black Death persecutions of 1348-49, with all Jewish property expropriated. A new community was established within a number of years. Jews traded in cattle and operated stalls in the municipal market as well as engaging in brokerage and money lending. In 1390 they were expelled by Rupert II together with all the Jews of the Palatinate. Few Jews lived in Heidelberg up to the late 17th century.
By 1743, 12 Jewish families were present as the community continued to expand despite local opposition. In 1724, Jews were admitted to Heidelberg University for the first time and maintained a student body of 19 throughout the century. With the annexation of Heidelberg to Baden, legal restrictions affecting Jews were gradually removed and full civil rights were granted. Nonetheless, anti-Jewish feeling persisted and Jews were attacked in the Hep! Hep! riots of 1819 and the revolutionary disturbances of 1848. The Jewish population grew to 445 in 1852 and 927 in 1900 (total 53,144). In 1876 a new synagogue and cemetery were consecrated. During the 19th century, the number of Jewish students at the University grew, reaching a peak of 76 in the 1884-88 period. Many came from Czarist Russia. Among Jewish lecturers and researchers a number chose to convert to advance their academic careers as the University remained a hotbed of anti-Semitism. Jewish students from Russia initiated Zionist activity after the First Zionist Congress in 1897. During WWI and after, Jewish refugees from Poland and East Galicia settled in Heidelberg, founding their own congregation. The Jewish population reached a maximum of 1,421 in 1925, dropping to 1,102 in 1933, with Jews remaining a leading force in the local economy, operating furniture and cigarette factories and large wholesale establishments. Most national organizations were represented there, including the Zionist youth movements. At the outset of Nazi rule, 34 Jewish professors were dismissed from the University and by 1935 one Jewish student remained in addition to those from mixed marriages. Jewish children were isolated in separate classrooms in the public school, and by the end of 1938 Jewish businesses had been completely "Aryanized". On “Kristallnacht” (9-10 November 1938), the synagogue was burned by the SS and SA; impounded religious articles and Torah scrolls were subsequently destroyed by university students. Jewish homes and stores were also heavily damaged and 150 Jews were detained in the Dachau concentration camp. About 800 Heidelberg Jews emigrated from Germany in 1933-1939, including a number who arrived after 1933. Fourteen Jews of Polish origin were expelled to the Polish border in 1938 and 1939. Another 281 were deported to the Gurs concentration camp on 22 October 1940. About 100 were saved from deportation by the Evangelist pastor Hermann Maas, who got them onto a sick list and during the period also arranged to get many Jews out of the country. (He was recognized by Yad Vashem in 1967 as one of the Righteous among the Nations.) On 22 August 1942 a further 111 were deported to the Theresienstadt ghetto. After the war a community numbering 260 in 1948 and about 100 in 1990 was reestablished by concentration camp survivors and former Jewish residents of Heidelberg.