The People's National Movement issued a statement around midnight Monday saying it had won.
The party said it fielded candidates in every electoral district on the island, securing 74 seats to United National Congress' 65 seats.
And the PNM thanked citizens "who have placed renewed faith" in the party.
"The PNM invites all our citizens to move forward with us in the interest of our beloved country" the statement read.
The PNM won a total of 74 seats while the UNC won 69.
In terms of control of the 14 corporations, the local government electoral map changed from 8/6 in the PNM’s favour to an even 7/7.
The PNM lost the battleground corporation of Sangre Grande, which fell to the Opposition, which won five of the eight seats.
The PNM, which won the Sangre Grande North West seat in 2016 by 40 votes, lost it to the UNC.