Sorensen won 101 caps for the national side in a 13-year career that began in 1999.
The 36-year-old's tally leaves him eighth in the all-time list for Denmark, 28 behind record holder and predecessor Peter Schmeichel.
"I have today made the announcement that I am finishing my international career," Sorensen wrote on Twitter.
"So proud to have represented Denmark 101 times. Time of my life."
Sorensen, who won his landmark 100th cap in March of this year, went to four major tournaments with his country, playing a major role in three of them.