Provided is a semiconductor package including an interposer. The semiconductor package includes: a package base substrate; a lower redistribution line structure disposed on the package base substrate and including a plurality of lower redistribution line patterns; at least one interposer including a plurality of first connection pillars spaced apart from each other on the lower redistribution line structure and connected respectively to portions of the plurality of lower redistribution line patterns, and a plurality of connection wiring patterns; an upper redistribution line structure including a plurality of upper redistribution line patterns connected respectively to the plurality of first connection pillars and the plurality of connection wiring patterns, on the plurality of first connection pillars and the at least one interposer; and at least two semiconductor chips adhered on the upper redistribution line structure while being spaced apart from each other.