The Vatican and Oman established diplomatic ties on Thursday, marking a further widening of the Holy See's official relations with the Arab Muslim World.
In a joint statement, both sides said they wanted to promote mutual understanding and cooperation and that ambassadors would be named.
The Vatican, a sovereign city-state surrounded by Rome, now has diplomatic relations with every country on the Arabian Peninsula except Saudi Arabia.
Oman, a Sultanate, is predominately Muslim, like the other countries on the peninsula. Oman has only four Catholic parishes and 12 priests, the Vatican said in a separate statement.
The Vatican hopes that with the upgrading of relations, the Church could continue to contribute to the social wellbeing of the country, the statement added.
Pope Francis visited Abu Dhabi in the United Arab Emirates in 2019 and Bahrain last year.
In both places, he attended inter-religious meetings to promote dialogue among faiths.