The last decades of research provided overwhelming evidence that compassion fosters a vast range of behaviors toward reducing suffering of others. In this regard, compassion has been described as a prosocial tendency par excellence, fostering helping behavior across a variety of social situations. With the present contribution, we apply a differentiated perspective on compassion. Building on just deserts theory, we argue that when other individuals suffer from unjust actions, compassion for the suffering individuals can foster harmful tendencies towards those who caused the suffering (i.e., third-party punishment). In Studies 1a to 1f, we examined a rich variety of situations in which unjust suffering occurs (i.e., terrorist attacks, sexual assaults, rape of children, and war) and documented a positive relation between compassion for suffering victims and punishment inclinations towards those who caused the suffering. Applying an experimental approach using various paradigms in Studies 2 to 6, compassion was shown to increase third-party punishment. Additional analyses revealed that (a) this increase occurs because compassion intensified moral outrage, which in turn predicted third-party punishment (Studies 2 to 6), and (b) compassion only fosters third-party punishment when suffering was caused by high (vs. low) unjust acts (Study 5). Overall, the present research reveals compassion in a different light in that harmful consequences of compassion are considered. Implications are discussed from a perspective of basic research on compassion and third-party punishment as well as from a societal perspective.