“Lunch with a loved one at school today,” the Dancing with the Stars alum, 25, captioned the image of son Tripp, 7, and 6-week-old daughter Sailor.
In the adorable image, the proud big brother sits at a lunch table while smiling and cuddling his baby sister.
Earlier this week, Palin shared a shot of the newborn on her personalized baby blanket.
And last week, the single mom posted a photo with both of her children as she headed back to work.
“Back to real life today! I was fortunate enough to take the last month off to stay home with my babies. Today marks the first time I’ve left SailorG, but I could not be more thankful she’s in the best of hands!!” she wrote.
The daughter of Sarah Palin – who who welcomed Tripp with ex-boyfriend Levi Johnston – was scheduled to marry Dakota Meyer over Memorial Day weekend, but the pair called off their wedding the week before.