Technology acquisition from external sources has been identified as a critical competence for sustained success in innovation, and research has paid a good deal of attention to studying its advantages, drawbacks, determinants, and outcomes. Traditionally, research has modeled the choice to acquire technology from outside a firm's boundaries as the result of a trade‐off between the benefits of external acquisition (e.g., higher return on investment, lower costs, increased flexibility, access to specialized skill sets, and creativity) and its drawbacks (e.g., opening the market to new entrants, risk of imitation of core competencies, and reduced value appropriability). Yet, this view does not capture the behavioral considerations that may potentially encourage or discourage managers from sourcing technology outside the firm's boundaries. This behavioral aspect is especially important if one wants to understand the conduct in external technology acquisition of family firms, which are found to favor strategic actions that preserve the controlling families' control and authority over business, even at the cost of giving up potential economic benefits. Thus, external technology acquisition is likely to be interpreted differently in family and nonfamily firms. Despite its importance, how the involvement of a controlling family affects decisions in technology and innovation management and specifically external technology acquisition is an overlooked topic in extant research and requires further theoretical and empirical examination. This study attempts to fill these gaps by extending the tenets of the behavioral agency model and prior research pointing to particularistic decision‐making in family firms to uncover the behavioral drivers of external technology acquisition in family and nonfamily firms. Theory is developed that relates performance risk, family management, and the contingent effect of the degree of technology protection on external technology acquisition, and the hypotheses are tested with longitudinal data on 1540 private Spanish manufacturing firms. The analyses show that managers are more likely to acquire technology from external sources through research and development contracting when firm performance falls below managers' aspirations. Family firms are generally more reluctant to acquire external technology, and the effect of negative aspiration performance gaps becomes less relevant as family management is higher, which is attributed to family managers' attempts to avoid losing control over the trajectory that technology follows over time. However, family firms become more favorable to considering the adoption of an open approach to technology development when some protection mechanisms (specifically, the filing of patents on the firm proprietary technologies) increase the managers' perceptions of control over the technology trajectory. As such, this study makes a contribution to the understanding of the behavioral factors driving external technology acquisition, and it offers important insights regarding technology strategy in family firms.