Power, defined as an individual’s perceived capability to influence others, is typically studied in work or romantic relationships, leaving it unclear whether findings can be generalized to other types of relationships, such as friendship. In this study, we applied a dyadic perspective to examine how power shapes relationship functioning between friends. We used an actor-partner interdependence framework with 248 friendship dyads to analyze four aspects of power (i.e., actor power, partner power, perceived partner power, desired power) and their links to global friendship evaluations (i.e., friendship satisfaction and friendship quality) and pro-relationship characteristics (i.e., compassion, trust, and forgiveness). We found that greater power in actors, greater power in partners, and perceptions of high power in friends were associated with more positive global friendship evaluations, higher compassion, and greater trust. By contrast, greater desired power was associated with more negative global friendship evaluations and lower pro-relationship characteristics. Control analyses showed that the findings were largely robust against potential effects of commitment and social desirability. The findings advance existing theories of power by (a) illustrating its dyadic nature, (b) showing that theories of power should incorporate friendship relationships, and (c) highlighting that some power-related findings may be context-specific and are not likely to generalize across different types of relationships.