Despite the many benefits of primary healthcare, persistent disparities disproportionately impact minority groups, marked by a higher prevalence of preventative health issues among African Americans and Hispanics compared to non-Hispanic White Americans. In addition, trends indicate a decline in U.S. adults having a primary care physician. Medical trust, particularly relevant in preventative care, significantly influences healthcare-seeking intentions among minoritized populations and poses a substantial barrier to women’s primary healthcare. Building on Andersen’s Behavioral Model of Health Services Use, this study’s purpose was to understand the influence of the waiting room environment on medical trust across different demographic groups. For this inquiry, we sampled African American, Hispanic/Latina, and non-Hispanic White women aged 18–40; groups disproportionately impacted by rising maternal mortality rates. Employing a sequential mixed-methods approach, including a questionnaire with 622 respondents and 25 interviewees, we uncovered that certain spatial characteristics and amenities, such as welcoming and calming environments, positively impact medical trust. Moreover, clear signage, well-maintained environments, and the inclusion of provider images and credentials (i.e., trust proxies) were similarly valued. Statistically significant different preferences also emerged, with African Americans prioritizing seating options, provider images, positive distractions, and the presence of ethnically similar patients at higher levels. Qualitative analysis indicated that trust proxies in the built environment had a greater impact on African Americans, while Hispanics appeared to be more influenced by person-centered characteristics. This study’s findings provide valuable guidance for those aiming to optimize waiting rooms for medical trust and, consequently, improve women’s healthcare outcomes.