On 5 October 2020, Millar joined League One side Shrewsbury Town on a short-term loan deal until January 2021 with an option to buy. He scored his first goal for Shrewsbury on 10 November 2020 in an EFL Trophy group game against Crewe Alexandra. After the club were unable to agree a deal for a permanent transfer, Millar returned to Australia on 19 January 2021.
