IMPORTANCE: The health effects of restrictive immigration and refugee policies targeting individuals from Muslim-majority countries are largely unknown. OBJECTIVE: To analyze whether President Trump's 2017 executive order 13769, "Protecting the Nation from Foreign Terrorist Entry into the United States" (known as the "Muslim ban" executive order) was associated with changes in health care utilization by people born in targeted nations living in the US. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study included adult patients treated at Minneapolis-St. Paul HealthPartners primary care clinics or emergency departments (EDs) between January 1, 2016, and December 31, 2017. Patients were categorized as (1) born in Muslim ban-targeted nations, (2) born in Muslim-majority nations not listed in the executive order, or (3) non-Latinx and born in the US. Data were analyzed from October 1, 2019, to May 12, 2021. EXPOSURES: Executive order 13769, "Protecting the Nation from Foreign Terrorist Entry into the United States." MAIN OUTCOMES AND MEASURES: Primary outcomes included the number of (1) primary care clinic visits, (2) missed primary care appointments, (3) primary care stress-responsive diagnoses, (4) ED visits, and (5) ED stress-responsive diagnoses. Visit trends were evaluated before and after the Muslim ban issuance using linear regression, and differences between the study groups after the executive order issuance were evaluated using difference-in-difference analyses. RESULTS: A total of 252 594 patients were included in the analysis: 5667 in group 1 (3367 women [59.4%]; 5233 Black individuals [92.3%]), 1254 in group 2 (627 women [50%]; 391 White individuals [31.2%]), and 245 673 in group 3 (133 882 women [54.5%]; 203 342 White individuals [82.8%]). Group 1 was predominantly born in Somalia (5231 of 5667 [92.3%]) and insured by Medicare or Medicaid (4428 [78.1%]). Before the Muslim ban, primary care visits and stress-responsive diagnoses were increasing for individuals from Muslim-majority nations (groups 1 and 2). In the year after the ban, there were approximately 101 additional missed primary care appointments among people from Muslim-majority countries not named in the ban (point estimate [SE], 6.73 [2.90]; P = .02) and approximately 232 additional ED visits by individuals from Muslim ban-targeted nations (point estimate [SE], 3.41 [1.53]; P = .03). CONCLUSIONS AND RELEVANCE: Results of this cohort study suggest that after issuance of the Muslim ban executive order, missed primary care appointments and ED visits increased among people from Muslim-majority countries living in Minneapolis-St. Paul.