The teenager reached the milestone birthday on Sunday 13 June and his parents, who separated in 2009, celebrated by posting throwback photos of their son to Instagram.
Price, 43, posted a video showing her second born son at different stages in his life from a baby to the present.
She wrote: "My absolute world! From the moment Junior was born he's been by my side, and now he has grown into a gorgeous little man and the world is his oyster ❤️❤️."
Andre, 28, also shared a video montage of various snap of his son through the years beginning with a cute picture of him with Junior as a baby.
He captioned the video: "16 years of pure Joy having you in my life. I love who you have become.
"Kind, funny, talented but most of all loving and respectful. Happy birthday my son. I’m proud to be your dad. Love you ♥️."
The proud dad added in a separate post that he had "lots of surprises" for his son.
Last year, the youngster shared that he was following in his parent's footsteps into the world of entertainment after landing a film role.
Read more: Junior Andre tests positive for coronavirus
He is the eldest of Andre's children, as the Mysterious Girl singer also shares daughter Princess, 13, with his ex-wife.
Andre went on to have daughter Amelia, seven, and four-year-old son Theo with second wife Emily.
Meanwhile, Price has son Harvey, 19, from a previous relationship with Dwight Yorke as well as son Jett, seven, and daughter Bunny, six, with ex-husband Kieran Hayler.
Watch: Katie Price says it's taken time to become friends with Peter Andre