Rt Revd John Pritchard retired from the post in October last year after seven years' service.
Under Church Of England election rules, no candidate received the required number of votes for nomination.
The Archbishop of Canterbury is chair of the group which looks after the election process.
Most Revd Justin Welby issued a statement explaining the situation. He said: "I am writing to advise that the Commission has been unable to discern the candidate whom God is calling at this stage to be the next Bishop of Oxford. Under the election rules under which we operate, no candidate received the required number of votes for nomination.
"The Crown Nominations Commission already has a number of meetings in place for the rest of this year. The Oxford CNC will reconvene on the 4th February 2016 with the second meeting on the 7th/8th March 2016. Bishop Colin will continue to provide oversight to the diocese as he has done over the past few months during the interregnum and I am very grateful to him for this.
"Many of you will have had the Crown Nominations Commission in your prayers and I thank you for them. I will continue to keep the diocese in my prayers over the next months.
"This will not be the news that you wanted to hear but please take this as a sign of our commitment to find the right person to be your next bishop."
Bishop of Dorchester (and Acting Bishop of Oxford) Rt Revd Colin Fletcher has expressed his disappointment over the delay. He said: "While it is clearly disappointing that the vacancy is being extended until later next year, it is of course vitally important that the right appointment is made.
"In the mean time I have every confidence in our senior staff to continue to work with God in growing the Church in this Diocese. We continue to commit the process into God's hands."
The diocese covers Berkshire, Buckinghamshire and Oxfordshire reaching out to 2.2 million people.
