Johannes Märtson (August 25, 1868, Lõve, Helme parish – January 9, 1935, Tõrva) was an Estonian politician. Pharmacist, the first Estonian mayor of the city of Valga, and thus the first Estonian mayor both in Estonia and in the world.

He studied at Viljandi elementary school, Tartu district and city schools. He was a pharmacy apprentice in St. Petersburg and Tartu. In 1893, he graduated from the University of Tartu as a pharmacist. He worked as a pharmacist in Tõrva and Valga. In December 1901, he participated in the Valga city council elections and achieved victory over the previously dominant German candidates in the city. On February 16, 1902, Märtson was elected mayor of Valga. He served as mayor until March 30, 1917, after which he moved to Tartu. While active in Valga, he participated in the founding of the Valga Estonian Society Säde in 1902, the Loan and Savings Association in 1903, and the Valga Mutual Credit Association in 1905, and was also a member of their boards. He was also actively involved in the establishment of Valga Secondary School and Valga Commercial School, as well as in the construction of the Säde Society's theater building. He was a member of the I and II Riigikogu as a representative of the Christian People's Party. From 1927 to 1929, he was a city councillor in Tartu.

Johannes Märtson died in Tõrva in 1935 and is buried in Helme cemetery.