"Happy Birthday Rob!! God blessed me beyond measure the day you were born," Rob's mother, Kris Jenner, wrote on Instagram, accompanied with a black-and-white snap of her son dressed in a classic black tuxedo. "You are the most amazing man who is kind, funny, smart and you have the best heart. You are beautiful inside and out and have brought so much joy into my life. Thank you for being the best son a Mom could ever dream of...I love you soooo much @robkardashian and I'm so proud of you. Mommy."
Khloe Kardashian's message -- which included a throwback pic of her, Rob and Kim Kardashian -- was just as sentimental.
"Happy birthday to my sweet brother! My best friend! My ace forever!!!" she wrote on her website, later posting a similar message to Instagram. "My love for you knows no bounds. You are and always will be my ultimate and all I ever wish for you on this day and everyday is your true and complete happiness. I love and adore you Rob!! No one will ever get our bond and I love that!"
Meanwhile, Kendall Jenner kept her birthday wish to Rob on her website simple and sweet. "Happy Birthday, Bobby!" she wrote. "Love you, you are such a light on this earth." It was later followed up with a group pic of her, Rob, Kylie and Kourtney Kardashian, proving they were taking selfies before it was even cool.
Kylie Jenner followed in her sister's footsteps, sharing a sweet vintage snap of she and Rob. "Happy Saint Patrick's Day & Happy Birthday Bobert," she captioned it.
Rob's friends also took to social media to send him birthday wishes, including Kourney's on-again, off-again boyfriend, Scott Disick.
"Love u bob happy bday," he captioned one of the four photos.
Although Rob's girlfriend, Blac Chyna, hasn't posted anything birthday-related on her social media accounts (yet!), the 27-year-old model helped her beau kick off his celebrations one day earlier at Legoland in Carlsbad, California.