ObjectiveThis study aimed to investigate the moderating role of sex in the relationship between conspiracy and (1) climate change anxiety, (2) eco-grief, and (3) eco-guilt among Arabic-speaking adults.MethodsThis cross-sectional study was conducted between May and July 2025 in Egypt, Jordan, Lebanon, and Palestine. Consenting participants completed an online questionnaire that included sociodemographic information, the Generic Conspiracist Beliefs Scale-5 (GCB-5), the Climate Change Anxiety Scale (CCAS), the Eco-Guilt Scale (EGuiQ-11), and the Eco-Grief Scale (EGriQ-6).ResultsIn total, 2,844 individuals completed the questionnaire. Sex significantly moderated the associations between general conspiracy thinking and climate change anxiety (β = −0.24, p < 0.001, ΔR2 = 0.005), eco-grief (β = −0.08, p = 0.007, ΔR2 = 0.002), and eco-guilt (β = −0.21, p < 0.001, ΔR2 = 0.006). Higher levels of conspiracy thinking was associated with increased anxiety about climate change among males (B = 0.42, p < 0.001) and females (B = 0.18, p < 0.001), with a stronger association observed in males. Similarly, the association with eco-guilt was stronger among males (B = 0.29, p < 0.001) than females (B = 0.08, p = 0.001). For eco-grief, the association was significant among males (B = 0.10, p < 0.001) but not among females (B = 0.03, p = 0.075).ConclusionThe findings suggest that the relationship between conspiracy thinking and distressing eco-emotions may be stronger among Arab males. Arab mental health researchers and practitioners may consider addressing distressing eco-emotions in individuals with stronger conspiracy thinking, while paying attention to potential differences between sexes.