The aim of this thesis is to evaluate the short and long term effectiveness of foot orthoses in the treatment of plantar fasciitis.Three studies were undertaken, the first two informing the third. The aim of the first study was to establish prescription habits of Australian and New Zealand podiatrists in order to ascertain the most commonly prescribed foot orthoses. The second study was conducted to establish the most appropriate outcome measure to assess the effectiveness of foot orthoses in the treatment of plantar faciitis. The main study, a pragmatic single-blind randomised control trial, was conducted to evaluate the effectiveness of three types of foot orthoses in the treatment of plantar fasciitis. The research concluded that provision of appropriate foot orthoses produces small short-term benefits in function for people with plantar fasciitis, but no effect is apparent at twelve months. / Doctor of Philosophy (PhD)