Five-times Grand Slam champion Sharapova became an ambassador for the UN Development Programme (UNDP) in 2007, but was dropped in March after admitting she had used the banned substance meldonium.
The United States-based Russian was originally banished from the sport for two years, a suspension that was later cut to 15 months.
She will return to action in time to contest three of the four Grand Slams next year, missing only the Australian Open.
"The UNDP is glad to learn that Maria Sharapova can return to the sport she loves sooner than expected and we will lift the suspension of her role as our goodwill ambassador once the reduced ban expires," the UN said in a statement.
The UNDP works to tackle inequality and poverty.
Image: Maria Sharapova
Photograph: Cameron Spencer/Getty Images