The Alias alum sported a white blazer, tank and shorts for the occasion.
Scroll through the gallery below to see more photos from Garner's night out!
The 13 Going on 30 lead smiled as she posed for the cameras.
As OK! previously reported, Garner celebrated her milestone birthday in a big way this year.
"I basically had a wedding for myself," the brunette beauty, who shares Seraphina, Violet and Samuel with ex Ben Affleck, said. "I was so shocked that I was doing it."
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Garner is known for being the girl next door, but she recently admitted there's another side to her that people don't always get to see.
"I'm not always just nice. I can also be salty, and I can be taciturn, or I can be really serious about what I want to get done. It's not that I feel I'm underestimated in that way—I'm not afraid to stand up for myself and say, ‘Just so you know, this isn't going to fly with me,'" she shared in a new interview.
"When that happens, I don't want you to be shocked that I'm a real person," she continued.
In the meantime, Garner's ex Affleck is now married to Jennifer Lopez, and there might be a ring in store for the mom-of-three, too, as things are getting serious between her and boyfriend John Miller.
“Ben and J.Lo’s nuptials have nothing to do with Jen and John’s plans,” a source explained of the couple. “They’d already decided they want a long-term future together."
“She’s met and hung out with John’s kids and his whole family, even for special events like birthdays, when they have all gotten together,” the source noted.