Pistorius, a multiple Paralympic champion who made history by running against able-bodied athletes at the 2012 Olympics, was convicted of murder for the Valentine’s Day 2013 shooting of Ms Steenkamp, 29, at his home.
The 36-year-old claims he shot Ms Steenkamp by mistake thinking she was an intruder.
Pistorius, behind bars for almost seven years, became eligible for parole after serving half of his 13-year prison sentence.
A parole board is to decide whether Pistorius should be let out early, after a hearing in Pretoria.
At the 2012 London Olympics, it took Oscar Pistorius 45.44 seconds to become a global icon.
The South African's 400-metre sprint was the first time in history that a double-amputee had raced at the Olympic Games.
His journey from disabled child to world-class athlete seemed to embody the very best of sporting endeavour and the human spirit.
Pistorius's world imploded after the murder of his 29-year-old model girlfriend and his 2014 trial saw him sat for months in a windowless courtroom.
A sparkling career was cut short, sponsors dumped him and he was forced to sell his homes to cover mounting legal bills.
A five-year conviction for manslaughter was upgraded to murder on appeal and in July 2016, he was sentenced to six years, less than half the minimum term for the charge..
In 2017, the Supreme Court of Appeal more than doubled that jail term to 13 years and five months after the state appealed that it had been unduly lenient.
Prosecutors had argued that Pistorius failed to show genuine remorse