Background: The Questionnaire on Attitudes Consistent with Sexual Offending (QACSO) is an assessment developed by Lindsay, Whitefield, Carson, Broxholme and Steptoe (2004). The QACSO was designed to assess cognitive distortions relating to sexual offending in males with intellectual disabilities (ID). Cognitive distortions form part of the offence chain in sexual offending and as such require effective assessment and treatment. Method: The QACSO manual and studies utilizing the QACSO were examined. Results: An overview of characteristics of the QACSO is outlined. The strengths and limitations of the measure are discussed, including validity and reliability of the measure and normative samples. Conclusions: The QACSO is a valuable tool in assessing cognitive distortions in intellectual disability sexual offenders. Whilst there are some concerns about validity and reliability which it would be beneficial to address, overall the measure has utility in forensic practice and research, and is unique for being developed specifically for intellectual disability offenders.