The development of increasingly sophisticated, easy, and diverse technology makes changes in people's behavior, especially in online buying and selling activities. At this time, social media has become a platform that is very popular with the public because it is very easy to make online buying and selling transactions. The purpose of this study was to determine the views of Islamic law regarding the legal requirements of online buying and selling transactions. The results of the study show that Islam allows buying and selling online, but there are some provisions that apply so that buying and selling online is legal and in accordance with the provisions of the sharia. A new sale and purchase transaction is declared to occur if three conditions of sale and purchase are met, namely: there are two parties conducting the sale and purchase transaction, namely the seller and the buyer; the existence of something or goods that are transferred from the seller to the buyer; there is a sentence that states the occurrence of a sale and purchase transaction.