As a new century begins for "The Modern Language Journal," we argue that highly effective pedagogy requires viewing language and language learning as both cognitive and social phenomena, and that teachers who seek to truly understand the nature of their responsibilities do not have the luxury of choosing one perspective over the other. We first identify what we consider to be theory-neutral nonnegotiable boundaries within which pedagogical decision making takes place, including (a) participants' background knowledge, (b) the nature of the object of instruction, (c) the nature of human cognition and social interaction, and (d) available time. Then we discuss learning goals, learning means, and instructional support as the negotiable elements that teachers may manipulate through their instructional decisions. At the heart of the article, we describe in greater detail cognitive versus social perspectives on the dynamic relationship between teaching and learning, and we identify ways in which they diverge and converge in characterizing linguistic development. We then synthesize these perspectives in a holistic, "sociocognitive" view of pedagogy, which we define as "a meeting of minds within social worlds." We conclude by outlining current pedagogical proposals that exemplify sociocognitive pedagogy by engaging learners in iterative cycles of modeling, guidance, and handover to independent language use.