Port Severn is a village at the mouth of the Severn River on the border between the Township of Georgian Bay and the Township of Severn, Ontario, Canada, situated on Highway 400 south of Parry Sound.

Port Severn is located at the western end of the Trent-Severn Waterway on Georgian Bay. The village is split by the river into two small communities. The community south of the river is administered by the County of Simcoe; the municipal offices for the Township of Georgian Bay are located in the northern part of the community.

This settlement was originally known as Severn Mills after a sawmill was built in 1830. Around 1850, lumber from this area was being sent out on ships; the village was renamed to Port Severn in 1868. In 1875, the Georgian Bay Lumber Co. was formed and became the major lumber producer in the Severn River watershed. The settlement expanded rapidly over the next 20 years. In 1896, the mill was struck by lightning and burned to the ground. Since the timber supply in the area had been greatly reduced, the mill was not rebuilt and the population of the village began to decline. With the completion of the Trent-Severn Waterway in this area in 1915, economic activity shifted from lumber to tourism.