The after-visit summary (AVS), a document generated from the electronic health record that summarizes patients' encounters with the healthcare system, is a widely used communication tool. Its use by and usefulness for populations with limited English proficiency (LEP) and limited health literacy (LHL) is poorly understood. In this cross-sectional study, we assessed use and usefulness of the AVS among English-, Spanish-, Cantonese-, or Mandarin-speaking Latinx and Chinese primary-care patients. Outcome measures were self-reported AVS use (did not use/looked-at only/shared only/looked-at and shared) and usefulness (useful/not useful). Among 993 participants, 57% were ≥65 years old, 61% had LEP, 21% had LHL, 30.2% were Latinx, 69.8% were Chinese. The majority used the AVS (86%) and found it useful (65%). In adjusted models, participants with LEP were more likely to "look at" (OR 1.68, 95% CI 1.07-2.62) and "look at and share" (OR 1.65, 1.02-2.66) the AVS, but less likely to find it useful (OR 0.68, 0.47-0.98) compared to English speakers. Those with LHL were less likely to "look at" (OR 0.60, 0.39-0.93) and less likely to find the AVS useful (OR 0.67, 0.46-0.99) compared to those with adequate health literacy. Our results emphasize the need for easy-to-understand and fully language-concordant AVS.