"Oscar specifically requested the memorial service as he continues to grieve and remains in deep mourning for the loss of his partner Reeva (Steenkamp)," a statement said.
Pistorius is charged with intentionally shooting dead Steenkamp, 29, at his house in Pretoria on Valentine's Day.
But the Paralympic and Olympic athlete says he mistook Steenkamp for an intruder in the dead of night.
Steenkamp, a model and law graduate, was cremated in her hometown, the southern city Port Elizabeth, last Tuesday -- the first day of Pistorius' bail hearing.
He repeatedly broke down crying in court at the mention of her name.
"Since it is such a sensitive issue, Oscar has asked for a private service with people who share his loss, including his family members who knew and loved Reeva as one of their own," the statement said.
Pistorius was released on bail last Friday and is due back in court June 4.