The extent to which tutors are interactive and engage in dialogue with a student tends to depend on their pedagogical expertise. Normally, tutors with pedagogical expertise are more interactive than tutors without pedagogical expertise. This finding, however, has largely been obtained when examining tutoring in procedural domains such as mathematics. Hence, less is known about the extent to which tutors engage in interactivity as a function of their pedagogical expertise when they tutor a conceptual domain such as biology. Therefore, we conducted a study with N = 46 tutors who differed in their pedagogical expertise and examined their interactive style of tutoring in a conceptual domain (Herppich et al. 2013, 2014). This article presents results of a content-based analysis showing that a tutor's interactivity resulting from combining more scaffolding with less explaining particularly promoted a student's deep learning. Contrary to prior research, however, tutors with more pedagogical expertise were less interactive and, consequently, fostered learning to a lesser degree than tutors with less pedagogical expertise. Our findings suggest that a more complete understanding of interactivity in tutoring requires a differentiated approach considering interactivity as a multifaceted phenomenon.