With Shamrock Rovers losing 3-0 at Cork City, Derry are now three points ahead of the Hoops although the Dublin club have a game in hand.
Wexford's Eric Molloy hit the Derry woodwork early on and Gerard Doherty had to make a couple of fine saves.
Derry also had good chances but a draw was probably a fair result.
Second-from-bottom Wexford, already beaten three times by Derry this season, started brightly as Paul Murphy headed wide and Molloy hit the woodwork in the eighth minute with Doherty beaten.
As Derry improved, Wexford defender Gary Delaney made a brave intervention to divert a Lukas Schubert header out for a corner and home keeper Graham Doyle then produced a superb double save to deny the lively Nathan Boyle and Barry McNamee.
Doyle's evening was a mixed bag as he made a number of fine reaction saves but also struggled to deal with a few tame shots from range.
Rory Patterson had the ball in Wexford's net in the 28th but the effort was correctly ruled out for offside.
Wexford enjoyed a good period just before half-time as substitute Jonny Bonner - on for the injured Delaney - hit a swerving shot inches over Doherty's bar and Murphy tested the Derry keeper with a headed effort.
In the second period, Derry looked the more likely side to break the deadlock as Doyle denied Boyle and Schubert got the ball stuck in his feet when he seemed certain to score after Wexford had failed to clear a Patterson free-kick.
But defeat would have been harsh for the home outfit after a battling display.
Derry City were held to a goalless draw by Wexford Youths in the League of Ireland but the result still strengthened their hold on third place.