Boy Meets World was filmed in a couple of different places.
The Matthews' house, the gang's apartments, and Pennbrook College were all filmed on sound stages in Los Angeles by Michael Jacobs Productions.
The High School that Corey, Shawn, and Topanga went to was real. It's still there as a matter of fact. It's Marshall High School, Los Angeles, California. Boston Public, The Wonder Years, Hang Time, Grease, Space Jam, Uncle Buck, Can't Hardly Wait, and Buffy the Vampire Slayer were all filmed here.