Gonzalez stands at 10-under-par 132, one shot removed from New Zealands Greg Turner, who also shot a Friday 65.
Padraig Harrington (67), Darren Fichardt (66), Dean Robertson (68), Peter Baker (68) and Richard Sterne (67) are all tied for third place at 8-under.
Harrington fired his second straight 67; though he said the rounds were far from mirror images.
You cannot believe the difference between those two rounds of golf, although on paper they are the same score, said the Irishman. Today I got away with a 67. Yesterday, a 67 was easily the worst score I could have shot.
Overnight leader Niels Boysen is now tied for 29th. The 27-year-old Dutch amateur followed an opening 64 with a Day-Two 75.
The 31-year-old Gonzalez almost won last years South African Open, but hasnt since come close to the winners circle.
Friday, he recorded an eagle and six birdies.
I have worked more on my game this year and tried to get a better swing, said Gonzalez. I am also now working with a psychologist who has helped a lot of players including two of my Argentine colleagues, Jorge Berendt and Gustavo Rojas. He has been very important.
Many of the big names are lurking not far behind Gonzalez. Bernhard Langer (67) and Miguel Angel Jimenez (65) are four off the lead at 6-under. Darren Clarke (70) and Ernie Els (70) are six off the pace at 4-under.
Full-field scores from the TNT Dutch Open