Jinn are spiritual beings featured in Islamic religions. They are described as one of the three races created by God, along with Humans and Angels. While the humans have been made with clay, and the angels with light, the jinn were made out of smokeless fire. They are usually invisible and seldom interact with humanity, but are capable of doing so. Despite their ethereal nature, they are nevertheless material beings much like men and unlike angels: the jinn live in their own societies and act according to their own free will, choosing whether they'll be good, evil or neutral.
Relation with aliens
The Quran talks about seven planets, and how of all the "creation" only the alumeen interact. "Alumeen" are the jinn, angels and human kind. Other verses state that amongst the alumeen, other "creations" exist. This can be or include "alien life", but as we have learned "only the alumeen interact". Therefore, if aliens exist, they cannot interact with us.