The 6,000 workers, who are represented by the International Association of Machinists, ratified the four-year agreement "by a majority of the voting membership," the union said on Wednesday.
"The negotiation committee would like to thank you for your patience and support in achieving another industry leading contract," IAM district 142 president David Supplee said in a union statement.
The contract includes 1.5 percent pay raises on the date of signing and for the first three years of the deal. In the last year of the contract, workers will receive a 2 percent raise.
"The new agreement rewards our IAM-represented employees for their exceptional performance, while supporting our mission of being the number one low-cost carrier in the country," Southwest said in a statement.
Southwest is currently in contract negotiations with its pilots and ramp workers, both who have asked for federal mediators to help with contract talks. It is also in contract talks with flight attendants and several other ground worker groups.