Jan Marius Romein (October 30, 1893 – July 16, 1962) was a Dutch journalist and historian.
Born in Rotterdam, Romein married the writer and historian Annie Romein-Verschoor on August 14, 1920.
Romein began writing while a student in 1916. After reading an article by Karl Marx in 1920, he became interested in Marxism, and after the couple moved to Amsterdam in 1921, he began writing for De Bleachers. Through the 1920s and 1930s he remained interested in the political development of the Soviet Union and of Asia. Romein survived World War II after being held hostage as Amersfoort, and returned to writing.
In 1937, he published an essay on technology called "The dialectics of progress" (in Dutch: "De dialectiek van de vooruitgang") in which he describes a phenomenon called the "Law of the handicap of a head start" ("Wet van de remmende voorsprong"), as part of the series "The unfinished past" (in Dutch: "Het onvoltooid verleden").
In 1946, Annie Romein received a copy of Anne Frank's diary which she tried to have published. When she was unsuccessful, she gave the diary to her husband, who wrote the first article about the diary and its writer, for the newspaper Het Parool. Interest raised by his article led to the diary being published the following year. By the early 1950s his communist beliefs had placed him in relative isolation, and in 1951 he was denied entry to the United States for an intended speaking engagement. He devoted the latter part of his life to writing a history of Europe from the year 1900. He died in Amsterdam.