Ira Remsen (February 10, 1846 – March 4, 1927) was an American chemist who introduced organic chemistry research and education in the United States along the lines of German universities where he received his early training.

He was the son of James Vanderbelt Remsen (1818–1892) and Rosanna née Secor (1823–1856) who came from family of Dutch settlers.

He did not complete his bachelor's degree but apprenticed for a while under a homeopathic physician who was on the faculty of New York Homeooathic Medical School.

He dropped out of this as well and joined the College of Physicians and Surgeons at Columbia University[4] receiving an MD in 1867 with a thesis on fatty degeneration of the liver.

He went to the University of Munich where he worked under Jacob Volhard (1834–1910) as well as one series of lectures under Justus von Liebig (1803–1873) who was the main attraction for Remsen to move to Germany.

[5] He then went to the University of Göttingen, on the recommedation of Friedrich Wöhler, and studied organic chemistry under Rudolph Fittig (1835–1910).

[1] Remsen's book and reputation brought him to the attention of Daniel Coit Gilman, who invited him to become one of the original faculty of Johns Hopkins University.

[11] Remsen had no interest in the commercial success of saccharin, from which Fahlberg profited, but he was incensed at the perceived dishonesty of not crediting him as the head of the laboratory.

[10] Fahlberg would soon grow wealthy, while Remsen merely grew irritated, believing he deserved credit for substances produced in his laboratory.

When the American Chemical Society gave him the Priestley medal in 1923 the citation would mention that Remsen served the science of chemistry and sought no commercial gains from his work.

[16] Throughout his academic career, Remsen was known as an excellent teacher, rigorous in his expectations but patient with the beginner.

He introduced many of the German laboratory techniques he had learned and wrote several important chemistry textbooks.

His ashes are interred behind a plaque in the chemistry building on the Homewood campus at Johns Hopkins University.