Kate, 45, wished her children Aaden, Alexis, Collin, Hannah, Joel and Leah a happy birthday in an Instagram post Sunday. The sextuplets' birthday coincided with Mother's Day this year.
Kate shared a photo of the Hershey's Kisses cereal she got her kids for their birthday. A streamer spelling out "Happy birthday" can be seen in the background.
"Happy 16th Birthday to my half a dozen 'Hershey Kisses', as they were called at birth! I love you so much! You're 6 of the sweetest things to happen to my life! Thanks for making every Mother's Day extra memorable!" Kate captioned the post.
"They requested 'junk cereals' for their birthday lunch (?!) so I got a bit carried away, as usual, and got them 21 different kinds! #Teenagers #AreFun #Sweet16 #HappyBirthdayMyBabies," she added.
Jon, 43, gave a special shoutout to Hannah and Collin on his own account. He told his four other sextuplets that he misses them and hopes they have a memorable birthday.
"Happy 16th to my six wonderful kids!! Been a long road I wish all the best!!! Wow 16!!!! Love you all!!!" Jon wrote.
Kate and and Jon also have 19-year-old twin daughters, Cara and Mady, who started college in 2019. Hannah and Collin live with Jon, who is not on speaking terms with Aaden, Alexis, Joel and Leah.
"The other four aren't talking to me, but they're talking to Hannah," Jon previously told People. "It's what the kids want to do. If they don't want to talk to me, that's fine, as long as they keep up with their sibling connections."
Jon shared a photo with Collin and Hannah in November from a family trip to St. Croix.
Kate and Jon divorced in 2009 after 10 years of marriage. The pair came to fame on the TLC series Jon & Kate Plus 8, which was renamed Kate Plus 8 following the couple's split.