A quasi-experimental design and multiple regression analysis were used to examine responses of 153 preservice general and special education teachers as a function of (a) participation in an introductory special education course and (b) viewing a co-teaching video (Friend, 2005) versus observing an inclusive classroom. Based on responses to pre- and post-measures (30 test-bank items, Mastropieri & Scruggs, 2010; Preservice Inclusion Survey, Shippen, Crites, Houchins, Tamsey, & Simon, 2005; and Teacher’s Sense of Efficacy Scale, Tschannen-Moran, & Woolfolk Hoy, 2001), results showed participants’ knowledge, attitudes, and sense of efficacy increased significantly from pre-to post-course survey (p < .001). In addition, participants who viewed the co-teaching video scored significantly higher on self-efficacy (p = .04) than those who observed in vivo. However, there were no differences in knowledge or attitudes (p .05) based on video versus observation. Finally, attitudes, but not knowledge, significantly predicted sense of efficacy (R2 = .21). Implications for teacher preparation programs are discussed.