The 47-year-old actress appeared on Katie Couric's podcast, Next Question With Katie Couric, on Thursday, and explained why she didn't want her eldest child with her ex-husband, Ben Affleck -- 13-year-old daughter Violet -- to join Instagram.
"Without even having parents who are well-known, I worry about all kids having to deal with this new pressure," she explained. "My daughter's at an all-girl school and it's such a huge problem."
Garner said the question of Violet joining Instagram has come up.
"She'll occasionally talk to me about getting Instagram and I can see why," she shared. "Because I'm on there and it's something kind of fun that I do, and I am modeling the opposite of what I want for her to do. How often is that in parenting?"
"I just say, when you can show me studies that say that teenage girls are happier using Instagram than not, then we can have the conversation," she continued. "But everything you look at, I don't see anything positive for you out there. You can look at mine when you want to, we can go over it together, but I just don't see it."
While Garner's children -- including 10-year-old Seraphina and 7-year-old Samuel -- are not allowed to join Instagram, they do occasionally film her for it. Earlier this month, Garner shared a post of one of her kids filming her crying during a sing-a-long screening of The Sound of Music at the Hollywood Bowl in Los Angeles.
"When your kid catches you misty-eyed at the Sound of Music sing-a-long. #idontcare #fraulinejen?? #perfectnightperfectmovie," she captioned the cute clip.
ET spoke with Garner earlier this month at Save the Children's "Centennial Celebration" gala at the Beverly Hilton Hotel, where she talked about her Halloween plans with her children. She admitted that planning things gets more difficult as they get older.
"I mean, I remember one year when I talked both my girls into dressing up as pigs, and they were so cute!" Garner recalled. "And now they would be like, 'No, Mom, ohmygosh, no!' So yeah, it's harder. But they're gonna be cute, whatever they are."
"I have kids that are funny and smart, and I think they're awesome," she added. "They change you wholly, and completely and not at all. I'm lucky to have them."