Windows and Doors Markham
Premium Fiberglass & Security Doors for Markham
Upgrade your Markham home or business with premium fiberglass and security doors supplied and installed by GEM Windows & Doors. Since 1961, our family-owned company has been trusted across the GTA for expert installations, durable products, and friendly service. Whether you’re planning a full renovation or need replacements for your windows and doors in Markham, our team delivers exceptional results with care, precision, and long-lasting performance.
Proudly serving Unionville, Thornhill, Angus Glen, Cornell, Buttonville, and surrounding neighbourhoods.

Awards and Recognition
A Legacy of Excellence in Windows and Doors
As Toronto’s oldest and most trusted window and door company, GEM Windows & Doors has built a reputation for quality and reliability. Our commitment to customer satisfaction has earned the trust of homeowners across the GTA, including many in Markham, who return to us for durable products and professional service year after year.





Featured on the cover of Fenestration Review for industry excellence

Member of Fenestration Canada, helping set CSA standards for windows and doors
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Services We Offer in Markham
Expert Door Installation in Markham
Our certified team provides seamless door installation in Markham, whether you’re upgrading to premium fiberglass, adding security doors for enhanced protection, or replacing older entry systems. We work around your schedule to ensure minimal disruption and long-lasting results. From product selection to the final installation, our process is designed to be smooth and stress-free.

Our Products
Premium Doors and Entry Systems for Markham
We offer one of the GTA’s largest selections of high-quality doors designed for strength, beauty, and performance:
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Fiberglass Doors: Built for durability and insulation, offering elegant designs that resist dents, scratches, and warping.
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Security Doors: Engineered with advanced security features for superior protection, without compromising style or curb appeal.
Our products are backed by reliable manufacturers, strong warranties, and ENERGY STAR®, giving you peace of mind and long-term performance with every installation.
GEM’s Price Match Guarantee
The Best Price, Without Compromise
At GEM Windows & Doors, we believe Markham homeowners deserve both quality and value. That’s why we offer our Price Match Guarantee:
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Bring us a written quote for an equivalent product and installation.
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Our experts will review and compare the specifications.
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If they match, we’ll not only meet the price, we’ll beat it by 10% of the difference.
This ensures you receive the best deal possible without sacrificing expert installation, Canadian-made quality, or the customer care we’re known for.

Over 60 Years of Quality and Trust
Since 1961, our family-owned business has proudly served homeowners in Markham looking for windows and doors that offer lasting value. From premium fiberglass doors to advanced security door options, our solutions are designed to enhance comfort, protection, curb appeal, and home value.
Visit one of Toronto’s largest showrooms to explore our wide selection and speak with our experienced team.

Frequently asked questions
What Customers are Saying


