The 31-year-old made her Scotland debut in 2008 and scored 24 goals in 144 appearances for her country. The Arsenal centre-back also represented her nation at the 2019 Women's World Cup.
"Representing Scotland has been an absolute honour and a dream come true," Beattie said.
"Thank you so much to every single staff member and player that has made my experiences so memorable and enjoyable. I've made friends for life."
