The London Borough of Harrow is one of the northern outer London boroughs: as such much of the Metropolitan Green Belt land is within the Borough boundaries. Parks and open spaces range from the large area around Harrow-on-the-Hill to the smaller gardens and recreation grounds; there are also a number of spaces taken up with golf courses. It has been suggested that Harrow is continuously losing its green space and trees.

Areas of open space include:

• Alexandra Park, South Harrow
• Bentley Priory, Stanmore: 165 acres (66ha) open space; Site of Special Scientific Interest and Local Nature Reserve
• Byron Park, Wealdstone
• Canons Park: 45 acres (18ha) 18th century parkland
• Chandos Recreational Ground, Edgware
• Grim's Dyke Open Space, Harrow Weald
• Harrow Park, Harrow on the Hill
• Harrow Weald Common, Harrow Weald
• Headstone Manor Recreation Park: 57 acres (230,000 m2) including the Museum and Headstone Manor & Bessborough Cricket Club
• Newton Park, Rayners Lane
• Pinner Memorial Park, Pinner
• Pinner Park Farm tenant dairy farmers Hall & Sons: total 230 acres (0.93 km2)
• Pinner Village Gardens, Pinner
• Roxbourne Park, Rayners Lane
• Stanmore Common: 120 acres (48ha); Local Nature Reserve
• Stanmore Country Park: 77.5 acres (31ha); Local Nature Reserve
• Stanmore Marsh, Stanmore
• Streamside Reservation, alongside Yeading Brook, Pinner
• The Grove Open Space, Lowlands Road, Harrow
• West Harrow Recreational Ground, West Harrow