Gordon & Helliwell was a Canadian architectural firm based in Toronto, Ontario. The principals were Henry Bauld Gordon, RCA, (1854–1951) and Grant Helliwell (1855–1953).

• Queen's Theological Hall, Kingston, Ontario, 1879
• Queen's University Kingston, Ontario, Arts Building, Queen's University, 1879-80 ^[1]
• Knox Church (interior), Toronto, Ontario, 1881
• St. Andrew's Presbyterian Church, Brampton, Ontario, 1881
• Upper Canada Bible and Tract Societies, Toronto, Ontario, 1886
• Kilgour Brothers' Building, Toronto, Ontario, 1886
• Bathurst Street Methodist Church, Toronto, Ontario, 1888
• Parkdale Presbyterian Church, Toronto, Ontario, 1888
• The Great Hall, Toronto, Ontario, 1889
• St. Peter's Church (addition), Toronto, Ontario, 1890
• Church of the Messiah, Toronto, Ontario, 1891
• 35 Rosedale Road, Toronto, Ontario, 1891
• Church of the Messiah Rectory, Toronto, Ontario, 1892
• Orillia Opera House (built as Orillia City Hall), Orillia, Ontario, 1895
• Harris Henry Fudger House, Toronto, Ontario, 1897
• 40 Maple Avenue, Toronto, Ontario, 1898
• Avenue Road Church, Toronto, Ontario, 1899
• 49 Elm Avenue, Toronto, Ontario, 1901
• 181 Crescent Road, Toronto, Ontario, 1902
• St. Peter's Anglican Church Rectory, Toronto, Ontario, 1905
• Oaklands (addition), Toronto, Ontario, 1906
• Wycliffe College, Toronto, Dining Hall and Dormitory Wing, 1907; Principal's Residence and new Chapel, 1911.^[1]
• Church of the Epiphany, Toronto, Ontario, 1911
• 18 Elm Street, Toronto, Ontario, n.d.