He is the son of Jane (nee Martin) and Philip Taptiklis. He is of one quarter Greek descent, with the rest of his ancestry being English and Scottish. His paternal grandmother, Barbara Jean Dorothy (nee Keech), was born in West Derby, England and had one quarter of a German ancestry, and his paternal grandfather, Nicholas Theodore Taptiklis, was born in Greece; they moved to New Zealand, where Theo's father, Philip, was raised. Theo's mother's family is from Glasgow, Scotland.