10 Smartest Doctor Who Characters

10. Adric

Companion to the Fourth and Fifth Doctor, Adric was a mathematical genius of E-Space. But his mathematical capability goes a little further than simple sums. Adric held the badge for mathematical genius on his planet of Alzarius. His greatest fear was facing a problem he could not solve, something which happened at the time of his death, with him quoting he “would never know if he was right”.

Adric was probably one of the Doctor’s most intelligent companions. He showed skill in using the TARDIS, as well as plenty of other alien technologies. To fans, as well as the Doctor himself, Adric was slightly annoying, however, there may be reasoning behind this view. Actor Matthew Waterhouse, who portrayed the character, admitted that he felt the Doctor saw Adric as a bit of a nuisance as he saw a lot of his younger self in him, which is quite the testament to Adric’s intelligence.

In fairness, the early '80s TARDIS team featured more than one intelligent companion. Tegan, while a decent companion, definitely wasn’t as bright as her fellow travellers, as she was originally an Austrialian stewardess. But Nyssa of Traken was highly intelligent like Adric. However, for this list, Adric is the one who takes this.