The ceremony will take place at Canterbury Cathedral on Wednesday and will be led by the Archbishop of Canterbury, Most Revd Justin Welby.
It is understood the 52-year-old, who describes herself in her Twitter profile as "more vulnerable than venerable", will become the first woman bishop to enter the House of Lords.
Her appointment, which comes after the Right Rev Michael Perham retired in November, means she is the first woman to run a diocese and is one rank below archbishop.
Hundreds of well-wishers are expected to make the journey from Gloucestershire to witness the historic occasion.
Archdeacon Treweek said she was excited for what lies ahead: "I am excited and full of anticipation and joy for what lies ahead as I begin my ministry as Bishop of Gloucester. I am looking forward to encouraging Christians to speak out with confidence about their faith and the good news that the Gospel brings.
"My calling to the role of bishop has been shaped by human encounter. I believe profoundly that relationship is at the heart of who God is. I have been with people through the joys and pains of their lives and it is these experiences that I will reflect upon as I take up this new role."
During the service the current Archdeacon of Hackney in the Diocese of London will be presented with her episcopal ring and pectoral cross, which were both designed especially for Rachel and represent her passion of conflict transformation, empowering others and her link with South Africa.
Before ordination, Rachel trained as a Speech and Language Therapist, a role she practised for more than six years. It was whilst working as a Speech and Language Therapist that she became interested in family dynamics.
Since 2011 Rachel has been a Member of Bridge Builders' Council of Reference.
Rt Revd Libby Lane was the first ever female to be made a bishop in the Church of England in January, becoming suffragan Bishop of Stockport, a bishop subordinate to diocesan bishop.
Her consecration came after the general synod gave the final seal of approval to the legislation on women bishops following its passage through Parliament last year.
The Rev Canon Dame Sarah Mullally, 53, a former government chief nursing officer, will also be consecrated as the Bishop of Crediton in the Diocese of Exeter in Devon.
