Barmby on the Marsh is a village and civil parish in the East Riding of Yorkshire, England. It is situated approximately 4 miles (6.4 km) west of the market town of Howden. It lies on the east bank of the River Ouse, near its confluence with the River Derwent. The west bank of the River Ouse at this point is North Yorkshire.
According to the 2011 UK census, Barmby on the Marsh parish had a population of 372, an increase on the 2001 UK census figure of 345.
Historically, Barmby on the Marsh was in the ecclesiastical parish of Howden in the wapentake of Howdenshire. From 1894 until 1974, Barmby was located in Howden Rural District. A section of the parish was transferred to Derwent Rural District in 1935.
In 1974 most of what had been the East Riding of Yorkshire was joined with the northern part of Lincolnshire to became a new English county named Humberside. The urban and rural districts of the former counties were abolished and Humberside was divided into non-metropolitan districts. The new organization did not meet with the pleasure of the local citizenry and Humberside was wound up in 1996. The area north of the River Humber was separated into two "unitary authorities"—Kingston-upon-Hull covering the former City of Hull and its closest environs, and the less urban section which, once again, named itself the East Riding of Yorkshire.