People with autism spectrum disorders (ASD) face discriminatory behaviours based on their condition, a consequence of prevailing negative attitudes in society. The main goal of this study was to adapt and validate the Societal Attitudes Towards Autism scale (SATA) for the Portuguese population. Additionally, we intended to examine possible factors that may influence current attitudes towards ASD. Participants were 377 adults from the general Portuguese population, with an average age of 38.55 years. The sample was collected online using self-reported questionnaires. Starting from the original factorial structure, four SATA models were tested. The final model showed adequate fit. This unifactorial model comprised 12 items, with two correlated error pairs. The internal consistency of the total scale was acceptable ([alpha] = 0.79), and the convergent validity was confirmed by significant correlations between the SATA and compassion, and empathy. Findings suggested temporal stability was adequate. Women aged 31 to 45 years, with more knowledge of and contact with ASD, and with an autistic family member, showed more positive attitudes towards ASD. The SATA seems to be a valid and reliable scale to measure the attitudes of the Portuguese population towards ASD.