ABSTRACT Animal-assisted interventions, such as the use of service dogs, represent an increasingly popular therapeutic avenue for youths with autism spectrum disorder (ASD). Before engaging anyone in this type of intervention, it could be justified to assess their level of attraction to animals. However, this aspect is rarely documented, and no existing instrument suits the specific challenges of ASD clients and the reality of the clinical setting. This paper describes the use and preliminary validation of an observation-based assessment tool developed by the Mira Foundation to evaluate the level of attraction toward dogs. The 9-item scale has been used by the team throughout the evaluation process of 1,010 potential candidates for a service dog. It is designed to describe and quantify observed behaviors during a standardized encounter with a non-familiar dog. The participants were aged between 2 and 26 years old (mean age = 8.13, SD = 4.3 years) and 87% had an ASD diagnosis. A total of 323 participants were assessed by a second rater, which allowed for interrater reliability analyses on each item of the scale. The factorial structure of the scale was determined by applying an exploratory factor analysis (EFA) on one-half of the sample, followed by a cross-validation study consisting of a confirmatory factor analysis (CFA) on the other half. Cronbach’s alpha was used to assess internal consistency. Based on weighted kappa statistics, interrater reliability showed strong agreement for individual items (Kw between 0.66 and 0.85). A two-factor solution was produced with EFA and confirmed through CFA. A Cronbach’s alpha of 0.89 when items from the first factor (attitude) were combined and 0.92 for the second factor (interaction) indicated good internal consistency for the identified subscales. These findings support the reliability of this assessment tool and its potential use in clinical and research domains.