Positive emotion sharing at work is linked to bonding, cooperation, and commitment, whereas negative emotion sharing is often associated with mixed or adverse outcomes (Barsade, 2002; Knight & Eisenkraft, 2015). Yet research mostly examines individuals and offers limited insight into how organization-level systems—such as affect climate (Parke & Seo, 2017)—shape sharing and its consequences. From a climate perspective, we argue that climates supporting authentic expression of both positive and negative emotions (positive and negative experience climate) promote helping-type organizational citizenship via employees' emotion sharing. We also hypothesize that these positive links are stronger when negative experience climate is high. Employees from diverse sectors completed surveys at three waves one month apart (N = 1,033). Measures assessed perceived positive and negative experience climate, emotion sharing, and helping. Path analysis showed that both positive (b = 0.33, SE = 0.06, p < .001) and negative experience climate (b = 0.28, SE = 0.05, p < .001) were positively related to sharing. Greater sharing predicted higher helping (b = 0.21, SE = 0.06, p < .001). Positive experience climate also had a direct positive association with helping (b = 0.15, SE = 0.07, p = .03). The interaction of positive and negative experience climate was significant for helping (b = 0.13, SE = 0.02, p = .02): the effect of positive experience climate on helping was positive when negative experience climate was high but not significant when low. Findings suggest that climates encouraging expression of both positive and negative emotions foster emotion sharing, which in turn promotes helping-oriented citizenship. The benefits of a positive experience climate appear amplified where negative experiences are also acknowledged; thus, organizations can strengthen cooperation and citizenship by cultivating climates that make room for sincere expression of not only positive feelings but also negative ones.