Redtop, also spelled Red Top, is an historic house located at 90 Somerset Street, Belmont, Massachusetts. It was once the home of William Dean Howells and family, and is now a National Historic Landmark.

The house was initially designed by William Rutherford Mead of the noted architectural firm of McKim, Mead, and White, and brother of Mrs. (Elinor Mead) Howells, while the Howells family lived nearby at their recently completed home on Concord Avenue in Cambridge. The new house Redtop was in fact owned by Charles Fairchild (1838–1910), Boston financier, who then rented it to the Howellses, but it was designed from the start for the Howellses' taste, with McKim becoming more and more involved. Construction began in 1877 and the Howellses lived in the house from 1878 to 1882.

Nearly every important American author of the time visited Redtop. To judge from published letters, Mark Twain visited Redtop eight times, and novelist Henry James wrote praising the house as a "fairy abode of light and beauty" on its "cheerful, breezy hill . . . I never saw a house that took my fancy more captive at once by its tone of colour--as soon as I had entered the door; and every subsequent impression deepened the effect. All the details struck me as purely lovely, and when I looked from within outwards and over that incomparable landscape . . . I said to myself, 'Well, good fortune can no further go. Let silence muse the amount of it!'"

The house sits on a large lot high atop Belmont Hill, looking out over Cambridge and Boston. It is built of brick and shingles in the Queen Anne style, with a large, sloping roof dominating the house as seen from the road beneath. The roof, once red, gave the house its nickname; but it is now gray. The shingles were later covered by a coat of stucco.

Mead's architectural designs for Redtop are preserved in the Amherst College Archives.