The giant house spider is a member of the genus Tegenaria and is a close relative of both the domestic house spider and the infamous Hobo spider. The bite of this species does not pose a threat to humans or pets. The giant house spider has the same colouration as the domestic house spider; it has earthy tones of brown and muddy red or yellow. They also have conspicuously hairy legs and abdomen.

Females can reach 18 mm in length, with males having a slightly smaller body at around 12 mm to 15 mm in length. The female leg span is typically around 45 mm. The leg span of the male is highly variable, with spans between 25 mm to 75 mm being common.