The 19-year-old has featured for the first-team on 10 occasions so far this season after making his debut in the 2-2 draw with Shrewsbury in September, but is yet to score his first goal.
Manager Gary Waddock told the club's official website: "Matt has all the qualities you look for in a young striker and I'm pleased to keep him at the club for two more years.
"He's got a great attitude, he works hard and he's always willing to learn from other professionals around the club. This is the right place for him to continue his development and hopefully he can become a regular in the first team for years to come."
McClure added: "It's a good club for youngsters to start their career and it's an exciting time to be here. We're pushing for promotion in my first season as a professional, I've been involved more than I thought I might have been and there could be a new stadium on the way, so it's all looking rosy.
"It's great for me that the gaffer's put his faith in me and Steve Hayes has put his faith in the gaffer to sign me up. Now I'm hoping to get more minutes under my belt, get that elusive first goal and kick on from there."
Source: PA
Source: PA