The adoption of sustainable technologies is strongly influenced by psychological and social factors, particularly for emerging solutions such as hydrogen fuel cell vehicles (HFCVs). These technologies embody the promise of environmental responsibility while simultaneously raising safety concerns. This study examines how value conflict—the internal tension between environmental attitudes and technological risk perception—influences the intention to adopt HFCVs. Data were collected through an online survey (N = 1330) using snowball sampling. Three attitudinal dimensions were examined—environmental commitment, technological risk perception, and adoption intention. Environmental commitment and risk perception represent the two underlying evaluative orientations whose discrepancy may generate internal value conflict. Based on these dimensions, a novel composite index, the Value Conflict Index (VCI), was constructed to capture the extent of this internal tension and its effect on adoption intention. Regression analyses show that both environmental attitudes and lower perceived risks are significant positive predictors of adoption intention. At the same time, VCI exerts an independent negative effect, confirming that internal dissonance reduces willingness to adopt. Women reported more substantial environmental commitment and higher perceived risks, leading to higher VCI values; however, moderation analysis indicates that gender does not change the behavioral impact of value conflict. These findings suggest that value conflict represents a general psychological barrier to the acceptance of sustainable technologies.