Dominant individuals have priority access to mates and resources. However, high rank can be costly too, especially when it is maintained by intense agonistic behavior. Oxidative stress has been proposed as a potential cost of social dominance. However, social dominance hierarchies can be dynamic, and few studies have examined the cost of social dominance when males are changing status. We studied temporal changes in markers of oxidative stress during social ascent in the East African cichlid fish Astatotilapia burtoni. After removing the dominant male, males ascended from subordinate to dominant status. On the first day of social ascent, immediately after the dominant male removal, the newly dominant male showed lower levels of plasma total antioxidant capacity (TAC). However, we found that liver TAC and liver superoxide dismutase, an enzymatic antioxidant, were significantly upregulated on day 1 and 2 of social ascent, respectively. By day 14, all markers of oxidative stress were similar to those observed in stable dominant males, which has higher levels of reactive oxygen metabolites (ROM) compared to subordinate males. We conclude that markers of oxidative stress vary dramatically during social ascent in a time- and tissue-sensitive manner. Our study provides a more nuanced look at the oxidative cost of social dominance and highlights the importance of considering temporal changes in markers of oxidative stress during important life-history events.