Dike, 17, has been with the Hammers since Under-11 level.
"It's something that a lot of people dream of,” he told the club's website. “I’m just grateful to be in a position where I can say that I've signed a professional contract. At a Club like West Ham United, it's obviously a great privilege, and I'm grateful for everyone that's helped me along the way.
“I want to thank God first. I used to pray for moments like this when I was younger. I want to thank my parents for the sacrifices they've made for me and the platform they've given me. My brothers, my sisters and all my friends as well for getting me through hard times.
“I come from humble beginnings,” he continued. “There aren't any footballers in my family that have become professional, so it’s special to be the first one to do it. It means a lot to my family and even our family back home in Nigeria as well. It's just a great day. It's something I've prayed for and worked on for a long, long time. For it to actually happen and become a reality, it's great.”
Always improving
Hammers academy chief Kenny Brown also said: “He’s been with us for a long time now, and we’ve seen him grow into a mature, intelligent young man. He’s got great technical ability, he’s added more dynamism to his game, and there’s more end product in his play now.
“This is a credit to Andre himself, as well as to the staff who work with him day in, day out. He comes in every day eager to improve. He’s well-liked in the dressing room, he’s humble and he carries himself the right way.
“Our aim is to help him push into the U21s set-up this season. He’s got the opportunity and the potential. Now it’s about continuing to work hard and take those next steps.”