A terrarium having a ventilation system for preventing condensation and moisture build up is provided. The terrarium includes a bottom wall and at least one side wall coupled together to form an animal enclosure therein. A ventilation system is disposed on a portion of the side wall configured to allow air to enter into the enclosure. The ventilation system has at least one opening positioned to allow communication between the inside and the outside of the terrarium. The opening is arranged such that air entering into the enclosure through the ventilation system is directed onto the inside surface of the side wall. The terrarium may include at least one side door to access the inside of the terrarium from the side. Further, the terrarium may include a bottom frame that raises the bottom of the terrarium from the lower edge of the bottom frame so that a heater may easily be placed underneath the terrarium.