The Metropolitan force say a full police service will be held at London's Southwark Cathedral beginning at 2pm.
It will be followed by a private cremation.
In a statement, his family said: "We want to thank everyone who has reached out to us over the past few days for their kindness and generosity.
"The police have been a constant, unwavering support and this very difficult time.
"It has made us realise what a caring, strong and supporting family Keith was part of during his career with the police. We can't thank them enough.
PC Keith Palmer died from stab wounds during the attack outside the Houses of Parliament.
Southwark Cathedral released a prayer following last week's attack in Westminster.
We look for peace, but find no good;
for a time of healing, but there is terror instead.
(Jeremiah 14.19)
God of peace,
God of healing,
on all caught up in the incident in Westminster
send both peace and healing.
Give to those who protect us
courage and commitment;
to those who govern us
wisdom and insight;
to those who are afraid
peace and assurance;
and to those who died
life eternal in your presence.
We ask this in the name
of Jesus Christ our Lord.
Amen