Vikna is a municipality in Nord-Trøndelag county, Norway. It is part of the Namdalen region. The administrative centre of the municipality is the village of Rørvik. Other villages in Vikna include Austafjord, Garstad, and Valøya.
The municipality of Vikten was established on 1 July 1869 when it was separated from the municipality of Nærøy. Initially, the population of Vikten was 1,749. On 1 January 1881, a small area of Fosnes (population: 61) was transferred to Vikten. The name of the municipality was later changed to Vikna.
The municipality is named after the three large islands in the municipality: Inner-Vikna, Mellom-Vikna, and Ytter-Vikna (Old Norse: Víkn). The name is derived from the word vík which means "cove" or "wick". (The islands are scored by numerous coves and inlets.)