Social interaction is key to students' learning in blending learning discussions. Although there is research on interactions in online courses and traditional classes, there is little on whether blended learning discussions are meeting students' social interaction and educational development needs. The purpose of this multicase study was to examine attitudes of first-year and final-year business and technology students and faculty members for patterns of interaction and knowledge construction. The study was conducted in the northeastern United States. Piaget's cognitive constructivism, Vygotsky's social constructivism, and Knowles's andragogy constituted the conceptual framework. Using maximum variation sampling, participants were 8 students and 4 faculty for 2 first-year and 2 final-year classes. Data sources were interviews and discussion responses coded using Straus and Corbin's open, axial, and selective coding procedures. Coded data were analyzed using Merriam's cross-case analysis method. The business students displayed the first three phases of knowledge construction: (a) sharing and comparing (b) discovery and exploration, and (c) negotiation of meaning; the technical students progressed to the fourth phase: testing and modification of proposed synthesis. Knowledge construction often occurred in a positive, challenging form of interaction. The professors expressed that gender, VoiceThread media, and discussion content influenced students' learning. These findings contribute to positive social change by informing stronger learning processes that students and teachers can use in their blended learning classes to facilitate collective knowledge construction.