Jacob Frankel (July 5, 1808 – January 12, 1887) was a German-born rabbi who became the first official Jewish military chaplain of the United States, during the American Civil War.

Frankel came from a Jewish family with a long tradition of musicians based in Grünstadt in the Palatinate which was then part of the French Empire, and was the son of Joseph and Dorothe Fränkel.

Frankel, at the time of Rabbi Leopold Roos, became cantor at his Grünstadt home synagogue, and in 1844 he moved to Mainz.

[5] From 1848 to a year before his death, Frankel served as the cantor and leader of the Rodeph Shalom Congregation in Philadelphia, Pennsylvania.

"[7] Frankel was appointed the first official Jewish chaplain in the United States Armed Services on September 18, 1862, by President Abraham Lincoln.