Growing interest in network dynamics has led to insights about patterns of network change, drivers of tie formation, and the temporal unfolding of the consequences of networks. To this area of inquiry, we introduce networking speed—the time that it takes for individuals to form a network tie—as an important but so far largely overlooked aspect. We develop a theory of networking speed that explains how different catalysts enable professionals to introduce variation into the speed with which they form interpersonal network ties. We discuss how such variation in the speed with which ties have been formed influences relational outcomes and the network returns that these ties generate. This discussion illustrates that high networking speed can entail advantages as well as pitfalls. We also explore temporal implications of networking speed—for instance, the persistence of the effects of speed over time. Overall, we conceptualize networking speed as a constitutive element of how interpersonal networks function in professional settings, and we propose a future research program for the integration of this novel concept into organizational network research.