The 23-year-old suffered the foot injury in Tuesday's behind-closed-doors friendly with Shrewsbury in which goals from Kyel Reid, who scored twice, Marlon Harewood and George Friend gave Wolves a 4-1 victory.
Wolves are top of the Championship and closing in on promotion to the Premier League, with Kightly having played a key role in their campaign.
Explaining his injury, Kightly told Wolves' website: "I jumped over the goalkeeper and just landed awkwardly when I planted my foot.
"It's the sort of challenge you go in for day-in day-out in training or in a game but obviously it just wasn't my day.
"The toe has got to be pinned and I will have to have an operation. I am absolutely gutted.
"To miss the last six games when we are in the position that we are in is the worst thing that could happen."