Truth and Reconciliation spokesman Vuyani Green on Friday said Williamson sought amnesty for the murders of Ruth First, and Jeanette Schoon and her daughter Katryn, in the early 1980s.
First was killed in Mozambique in 1982. Schoon and Katryn were killed in Angola in 1984.
Green said the hearings would be held at the Idasa Centre in Pretoria as from Monday.
Former police commissioner Johan Coetzee, ex-Vlakplaas police base commander Eugene de Kock, Williamson and five others want amnesty for bombing the London offices of the African National Congress.
In Benoni, Tebogo Kebotlhale, Molwedi Mokoena, Phumzile Sigasa and Elgas Mabore Ndhlovu, who declared themselves ANC members, will seek amnesty for a Wimpy Bar bombing and an ambush outside Lindela hostel in Katlehong on the West Rand in 1988.
Green said in its evidence to the TRC last year, the ANC included the bombing in a list of attacks of which it said: "... we are uncertain as to whether these attacks were carried out by bona fide Umkhonto weSizwe cadres."
One person, Maryann Serrano, was killed and about 60 were injured in the Wimpy bombing.
In Cape Town, four Pan Africanist Congress members will be seeking amnesty for armed attacks around the city before the 1994 elections.
Six people died including two policemen during these incidents, said Green.
The applicants are Walter Tanda, Andile Shiceka, Gcinikhaya Makoma and Mandla Maduna.
Other hearings, scheduled for late September, included the so-called Caprivi trainees, Afrikaner Weerstandsbeweging members responsible for pre-election bombings in 1994, and the Bophuthatswana policeman who killed three AWB members during their invasion of the former homeland, said Green.
He said the venues and dates for these hearings group would be announced later.