Would this fit a 2018 Mazda bt50?

Hi Anne, thank you for your inquiry, The Rectangular autoshade is universal for most rectangular doors so this should be suitable for your vehicle. We hope this helps. if you follow the link https://www.babyonthemove.co.nz/store-locations/ this will take you to our online store finder. Here you can find contact details for your nearest Baby On The Move Store where one of our team experts will be happy to assist you in your product search and help answer any further questions you may have.