"Congratulations My Sweet Kylie! What a magical ride it's been! I'll miss you bumping along with me," the 33-year-old reality star captioned the post, which had received over 6.8 million likes as of Monday morning.
"Never in a million years did I think we would do this together but it's been that much more special because of it. God is so great!! He had His plan all along! I love you little mama," she added. "love big mama."
Jenner announced her baby girl's birth Sunday afternoon following months of pregnancy rumors. She explained in an Instagram post that she kept her pregnancy quiet to protect her health and her family's privacy.
"I knew for myself i needed to prepare for this role of a lifetime in the most positive, stress free, and healthy way i knew how," the 20-year-old star said. "I knew my baby would feel every stress and every emotion so I chose to do it this way for my little life and our happiness."
Jenner's mom, Kris Jenner, was among those to also congratulate the new mom online.
"God is SO good!! I am so excited and thrilled to welcome another precious baby girl to our beautiful, ever growing family. We are blessed beyond belief!" she tweeted.