Greek Orthodoxy and Catholicism are two of the largest branches of Christianity, and while they share many similarities, there are some key differences between them:

1. Theology and Doctrine: Greek Orthodoxy and Catholicism have different approaches to theology and doctrine. Greek Orthodoxy is more focused on tradition and the teachings of the early Church fathers, while Catholicism places a greater emphasis on the authority of the Church and the teachings of the Pope.
2. Leadership Structure: In Greek Orthodoxy, the bishops are considered equal and autonomous, with no one bishop having authority over the others. In contrast, in Catholicism, the Pope is considered the supreme authority, and bishops are appointed by him.
3. Liturgy and Worship: Greek Orthodoxy and Catholicism have different liturgical practices and worship styles. Greek Orthodoxy tends to have a more formal and traditional worship style, with a heavy emphasis on icons and symbolism. Catholicism has a more diverse range of liturgical practices, with different forms of worship for different occasions.
4. Sacraments: Greek Orthodoxy and Catholicism both recognize seven sacraments, but there are some differences in how they are administered and understood. For example, in Greek Orthodoxy, the sacrament of Confirmation is given immediately after baptism, while in Catholicism it is usually administered later in life.
5. Spirituality: While both Greek Orthodoxy and Catholicism share a focus on prayer and spiritual growth, there are differences in their spiritual practices. Greek Orthodoxy places a strong emphasis on asceticism and mysticism, while Catholicism has a more varied approach to spirituality, with different religious orders emphasizing different practices.

It’s worth noting that these are general differences, and there is a great deal of diversity within both Greek Orthodoxy and Catholicism. Additionally, there are many similarities between the two branches of Christianity, including a shared belief in the Holy Trinity, the authority of the Bible, and the importance of Christ’s death and resurrection.

If you’d like to know more about what version of the Bible is used in Greek Orthodox churches, click here.