<p>Cost stickiness has become a prominent research focus in management accounting. This study investigates cost stickiness from the perspective of peer effects. Using data from Chinese A-share listed companies from 2004 to 2024, I find that cost stickiness exhibits peer effect, with the cost stickiness of peer firms positively correlated with that of the focal firm. Mechanism analysis identifies the effectiveness of information transmission and market competition as key factors driving the peer effect of cost stickiness. Further examination indicates that the peer effect is driven by firms with sticky cost behavior, while firms exhibiting anti-stickiness do not demonstrate peer effects. Moreover, managerial power suppresses the peer effect of cost stickiness, while it is more pronounced under high economic policy uncertainty. This research not only contributes to the understanding of the external determinants of cost stickiness but also provides novel evidence regarding the economic consequences of peer effects.</p>