Doyle, the reigning two-time U.S. Senior Open champion, holed a 10-foot birdie putt at the 17th hole to break a tie with O'Meara and Wadkins. He is at 12-under 132 overall.
Wadkins, the overnight leader, followed up his first-round 64 with a 3-under 69. O'Meara had a 4-under 68 to join him in a tie for second place at 11-under 133.
Mike Reid had his second-consecutive 67 and stands alone in fourth place at 10-under 134. Ireland's Des Smyth (67) and Argentina's Eduardo Romero (69) are a shot further back at 135.
Doyle played in a threesome with O'Meara and Wadkins, but was the last one to post a birdie. He made his first at No. 5, then followed it up with his only bogey of the round to fall two shots behind both O'Meara and Wadkins.
Over the last 10 holes, however, Doyle made his move by scattering five more birdies while his playing partners made just two apiece.
With his homespun swing, Doyle has won 11 Champions Tour titles since he broke through with a win at this event in 1999 -- this after never finishing better than seventh on the PGA TOUR.
The 58-year-old former amateur star is a career 5-5 when holding the lead heading into the final round of a Champions Tour event.
Sunday at Quail West, there will be 12 players within five shots.
O'Meara and Wadkins both posted bogey-free rounds, but they had just four and three birdies respectively.
Defending champion Loren Roberts is six shots back at 138 following a second- round 70. Roberts made this tournament his third straight win to begin last season -- a Champions Tour first.
He is tied for 14th place with five other players, including the man he battled -- and ultimately lost out to -- for last year's Charles Schwab Cup title, Jay Haas.
Peter Jacobsen (back) and Jay Sigel (ribs) both withdrew from the event before their scheduled tee times.
J.C. Snead made the first hole-in-one on the Champions Tour this season when he aced the 172-yard, par-3 12th with a 5-iron. Snead carded a 72 and is tied for 57th place at 1 over par.