The Catalan club opened a permanent office in New York in September, and have six academies across the US.
A statement from Barcelona said they had "approved a development plan for women's football in the US... in order to participate in the NWSL from 2018".
There are 10 franchises in the NWSL, which has never had a European side competing.
But the NWSL confirmed it "looked forward to continuing discussions" with Barcelona over the move.
The Catalan club's current team are joint-top of the Spanish top tier - which contains a mixture of full-time and semi-professional teams - with two matches remaining.
The team, founded in 1988, reached the last four of the Champions League for the first time this term before losing 5-1 on aggregate to Paris Saint Germain.
BBC World Service reporter Sarah Mulkerrins:
Barcelona have targeted women's football in the US as a way to grow the club's brand globally. When they opened their New York office, president Josep Bartomeu raised the issues of a women's team and said he had spoken with then NSWL chief Jeff Plush, and United States Soccer Federation president Sunil Gulati.
Plush has previously said he only wanted an even number of teams in the league, so Barca's entrance could open the door for another major club.
Barcelona are in talks with the American National Women's Soccer League (NWSL) about entering a team for 2018.