Abstract Background/Aims Recent research on mindsets has shifted from understanding its homogenous role on performance to understanding how classroom environments explain its heterogeneous effects (i.e., Mindsets × Context hypothesis). Does the macro context (e.g., societal level of student mindsets) also help explain its heterogeneous effects? And does this interaction effect also apply to understanding students' well‐being? To address these questions, we examined whether and how the role of students' mindsets in performance (math, science, reading) and well‐being (meaning in life, positive affect, life satisfaction) depends on the societal‐mindset norms (i.e., Mindsets × Societal Norm effect). Sample/Methods We analysed a global data set ( n = 612,004 adolescents in 78 societies) using multilevel analysis. The societal norm of student mindsets was the average score derived from students within each society. Results Growth mindsets positively and weakly predicted all performance outcomes ( r s = .192, .210, .224), but the associations were significantly stronger in societies with growth‐mindset norms. In contrast, the associations between growth mindsets and psychological well‐being were very weak and inconsistent ( r s = −.066, .003, .008). Importantly, the association was negative in societies with fixed‐mindset norms but positive in societies with growth‐mindset norms. Conclusions These findings challenge the idea that growth mindsets have ubiquitous positive effects in all societies. Growth mindsets might be ineffective or even detrimental in societies with fixed‐mindset norms because such societal norms could suppress the potential of students with growth mindsets and undermines their well‐being. Researchers should take societal norms into consideration in their efforts to understand and foster students' growth.