Why do some firms increase R&D investments in the face of uncertainty, while others do not? Contrary to common wisdom, this study posits that uncertainty prompts firms to invest in R&D. The value to invest under uncertainty is, however, bounded by a firm's learning conditions (i.e., human capital, relatedness of innovation activities, and industry maturity). An empirical test on a cross-industry panel of 551 business divisions of manufacturing firms reveals how organization-environment interactions determine the firm-specific value to invest in learning prior to full-scale commercialization. The insights help to bridge real options theory and the learning literature.