A Fansite is an unofficial fansite created without the direct permission or consent of Blue Fang Games or Microsoft, run primarily by fans. They have been hosted on a variety of sites include Tripod, Webs, and InvisionFree, but currently the vast majority of Zoo Tycoon 2 sites are hosted on ZetaBoards message board software. These sites typically host content including sceenshots, storylines, strategies, designing topics, wishlists, and Downloads. Active fansites typically exceed 2,000 members.

For many years, the Official Zoo Tycoon website maintained a list of fansites, but after the release of Zoo Tycoon 2: African Adventure they stopped due to the inability to maintain it and lack of consistency. They also offered 'fansite kits', which included transparent images of animals and logos for Zoo Tycoon 2 and it's expansions.

Currently, the most active fansites for Zoo Tycoon 2 are The Round Table, Gaia, and Zoo Tycoon Volcano, and other fansites include ZT2 Designing Centre and Zoo Admin, while the most active fansites for Zoo Tycoon' remain Zoo Tek Phoenix and Zoo Admin.