The team did not disclose terms of the contract, but a source told ESPN's Jenna Laine that Wilcox agreed to a two-year deal worth $8 million.
"I hated him the past couple years," said new Buccaneers receiver DeSean Jackson, who was present when Wilcox walked into the building Saturday. "He was a Cowboy and I was a Redskin, so we really didn't like each other. Now we're on the same team so I don't have to worry about him hitting me."
Despite missing three games with a thigh bruise, he was better in coverage than the previous year and finished the season with 49 tackles, six pass deflections, an interception and one forced fumble.
The Cowboys selected Wilcox in the third round of the 2013 draft after playing safety for just one season at Georgia Southern, where he mostly played running back.
He started five of 13 games as a rookie and moved into a full-time starting role with the Cowboys in 2014, finishing with 74 tackles and a career-high three interceptions. While he was a big hitter, he was inconsistent in coverage.
ESPN's Todd Archer contributed to this report.