This study examined two effective teaching behaviors traditionally considered by instructional communication scholars to associate positively with students' academic experiences: instructor clarity and immediacy. Our study situated these teaching behaviors in a conditional process model that integrated two key assumptions about student learning: (a) the process by which student learning occurs is due, in part, to the sustained attention that students give to effective instructors (a mediated test of learning) and (b) some students self-regulate their learning despite the (in)effectiveness of the teaching they receive (a moderated test of learning). Three hundred and sixty-two college students were randomly assigned to one of four lecture conditions that manipulated instructor clarity and nonverbal immediacy in a 2 × 2 factorial experiment and completed post-test assessments including a test of cognitive learning. Results indicated that: (a) clear instruction with or without nonverbal immediacy cues directly increased students' test scores by over one letter grade on average; (b) the added benefit of nonverbal immediacy to clear instruction slightly increased test scores, but only indirectly through students' sustained attention; and (c) removing nonverbal immediacy from clear instruction proved detrimental only for students who were not self-regulated.