Purpose <p>Non-or minimally speaking (NMS) autistic individuals are an understudied portion of the autism spectrum, particularly in adulthood. Efficient, validated measures of daily living skills (DLS) are needed to promote the inclusion of NMS adults in research. This study examined the validity of the Waisman Activities of Daily Living (W-ADL), a brief, caregiver-report DLS measure, in NMS autistic adults by comparing it to the Comprehensive Parent/Caregiver Form, a survey version of the Vineland Adaptive Behavior Scales, Third Edition (VABS-3:Survey).</p> Methods <p>Caregivers of 94 NMS autistic adults (Mage = 20.66, SD = 1.45) completed both the W-ADL and the VABS-3:Survey. Criterion validity was examined by comparing W-ADL and VABS-3 DLS scores across parent-reported expressive language levels. Convergent validity was assessed via correlations between W-ADL total scores and VABS-3 Adaptive Behavior Composite, DLS domain, and DLS subdomain scores. Content validity was evaluated through conceptual item matching.</p> Results <p>W-ADL scores varied by expressive language level in a pattern consistent with VABS-3 scores and were strongly correlated with VABS-3 DLS domain and subdomain raw scores. Conceptual item matching demonstrated substantial overlap between W-ADL and VABS-3 DLS items, particularly for personal and domestic skills. In contrast, W-ADL coverage of community-based DLS was limited.</p> Conclusion <p>This study provides support for the validity of W-ADL as a measure of DLS in NMS autistic adults. Availability of valid, open-access, low-burden measures such as the W-ADL is an important step toward better characterization of NMS research samples and increasing research on the characteristics, strengths, and challenges of NMS autistic adults.</p>