The 2015 passing of Every Student Succeeds Act (ESSA) to replace No Child Left Behind was celebrated within the arts community (Arts Education Partnership, 2017; National Art Education Association, 2017; Walker, 2016) for embracing a "well-rounded education" that explicitly includes the arts in its definition (ESSA, 2015, p. 298). In 2009, prior to ESSA's passage, the Institute of Museum and Library Services (IMLS) released the report "Museums, Libraries, and 21st-Century Skills" to underscore that museums and libraries are learning pillars that support 21st-century skills, which include critical thinking and problem solving, creativity and innovation, and visual literacy, among others. In the decade following the IMLS report (2009), "21st-century skills" became common museum parlance. The authors of this article, evaluators working with all types of museums nationwide, received regular requests for evaluations of programs and exhibitions that foster 21st-century skills. But while museums were working to support students' well-rounded education as a 21st-century learning pillar, the evidence of museums' impact on students was lacking (Terrassa et al., 2016). Two independent studies about the effects of single-visit art museum field trip programs, art museums' most common outreach to schools (RK&A, 2015), provide such evidence. In this article, the authors present the results of these two studies along with a description of art museum pedagogy.