The Aberdeen Asset Management Australian Equities team will manage the mandate, with more than 10 years' experience managing Aberdeen's Australian small companies portfolios.
IOOF group head of research and portfolio construction Matthew Drennan said Aberdeen's "high conviction approach to managing equities" helped seal the deal.
"We believe [Aberdeen's] investment process, with its focus on fundamental research, is particularly well-suited to finding quality small companies with the potential to outperform the market," said Mr Drennan.
Aberdeen's managing director in Australia, Brett Jollie, said the new mandate would broaden his firm's relationship with IOOF.
"It is an endorsement of Aberdeen’s rigorous approach to managing equities and of our Australian Equities team, which is building a solid reputation for delivering for clients in the small caps space," Mr Jollie said.
A spokesperson for Aberdeen declined to reveal the size of the mandate.