A bruising 12-round battle that featured several close rounds finished with Haney, shading it on all three scorecards with judges, scoring it 116-112, 115-113, 115-113 in his favour.
The unbeaten Haney, who improves to 30-0 with 15 knockouts, started the fight aggressively to win the opening round.
But veteran Lomachenko battled back brilliantly to land several hard shots in the second and third rounds, wobbling Haney with a solid uppercut in the third.
Haney appeared to just gain the edge in the middle rounds of the fight before Lomachenko finished strongly with the crowd in the MGM Grand Garden Arena roaring the former champion on.
Haney though rocked Lomachenko with a left hook in the seventh round and continued to find his target with crisp, counterpunching even though the Ukrainian eventually landed more punches throughout the fight, 124 to the American's 110.
The win means Haney retains his World Boxing Association, World Boxing Council, International Boxing Federation and World Boxing Organization belts.
He became the first undisputed lightweight world champion since Pernell Whitaker in 1990 with a lopsided decision over George Kambosos in Melbourne in June 2022.
Lomachenko returned to the ring in October last year, after enrolling in a territorial defence unit for Ukraine after the invasion of the country by Russia.
The veteran's record fell to 17-3 with 11 knockouts after Saturday's defeat.
