Khawaja's 63 has helped steer Queensland to 4-147 at tea on Wednesday's opening day at the Gabba.
The Bulls skipper, who opened the innings, has now made two Test centuries, two Shield tons and four Shield half-centuries this summer.
Khawaja's feats on Wednesday came after NSW won the toss on a bowler-friendly pitch.
His Test teammate Marnus Labuschagne made only eight before not offering a shot to an offcutter from Trent Copeland (1-34).
The ball brushed Labuschagne's back pad and he was clearly upset to be given out lbw, indicating he believed the ball would have travelled over the stumps before shaking his head when trudging off.
Labuschagne's dismissal followed the early loss of opener Bryce Street (five), who was caught at first slip by Copeland from the bowling of paceman Chris Tremain (2-15 from 13 overs).
Matthew Renshaw made 12 before attempting a pull shot from Tremain's bowling, only to get a top-edge which lobbed to Harry Conway at wide mid-on.
Khawaja's 155-ball innings ended just before tea when he attempted a flashy off-drive from the bowling of Jack Edwards (1-13) but edged to Copeland at first slip.
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