It's best to double-check and enter the specific address in the School Assignment Tool
Or, call the School Boundary Information Line at 240-314-4710. Not all homes for sale in each school district will show (on any real estate site).  For different reasons, some listings don't indicate their corresponding H.S.
You can do your own home search, and then enter the home's address in above School Assignment Tool. 

Montgomery County High Schools

BCC - Bethesda Chevy Chase

Blair - Montgomery Blair

Blake - James Hubert Blake

Churchill - Winston Churchill

Clarksburg

Damascus

Einstein - Albert Einstein

Gaithersburg

Kennedy - John F. Kennedy

Magruder - Colonel Zadok Magruder

Paint Branch

Poolesville

Richard Montgomery

Rockville

Sherwood

Springbrook

Walter Johnson