The former Zimbabwe prime minister died in Singapore, Zim Live reported.
It is believed he had been receiving treatment there since April.
Mugabe had led Zimbabwe in 1980 and again in 2017, amid accusations of intimidation and vote rigging.
But he was ultimately booted from power after a 2017 military coup.
Lawyer Fadzayi Mahere tweeted: “Rest In Peace, Robert Mugabe. My response to your passing is complicated. I’m going to write a long piece. However, for now, deepest condolences to his family.”