This is a list of collisions between exoplanets or planetesimals observed in extrasolar systems. These collisions are more common in young systems and are an important part in the growth of especially terrestrial planets from so-called planetary embryos. Detections of individual collisions are nevertheless rare and are detected via transits in the optical, infrared excess, silicate emission or via infrared brightening. Collisions are thought to be common in a type of debris disk, so-called extreme debris disks (EDD). Co-moving stellar or substellar companions can trigger such collisions at an old age, creating old EDDs. Only about 24 EDDs are known. HD 181327 has an asymmetry in its disk that could be explained by a giant collision, but later research excluded this scenario.
This list does not include planetary bodies being accreted by white dwarfs, for this refer to the List of exoplanets and planetary debris around white dwarfs.
This list contains systems with individual collision events that were directly observed. Alternatively events were inferred from properties of the disk. The list is sorted after the start of the event.
These objects appear as EDDs in Moór et al. EDDs are listed here, because they are often associated with individual giant collisions. List is sorted after discovery year.