The Good Religion is divided into the following schools:
"Traditionalist": those who believe in "traditional" Zoroastrianism, the kind practiced by most Zoroastrians. They do not believe that anyone can convert to Zoroastrianism; one must be born into it.
"Modernist": those who believe in the traditional scriptures and rites of Zoroastrianism, but believe that outsiders can convert to the Good Religion, although they do not proselyte.
"Restorationist": Those who believe that only the Gathas (hymns of Zoroaster) are inspired of God. All later Zoroastrian scriptures and rituals are considered "man-made" and thus not inspired of God, and optional for Zoroastrians. They believe they can proselyte.
These are the following sects:
Masdayasni: Iranian Zoroastrians. About 100,000, but no good statistics are kept. Most are Traditionalists. The Masdayasni are divided into two sects which are exactly alike except they keep two different calendars.
Parsee: Indian Zoroastrians who live mostly in Mumbai (Bombay). Most are Traditionalist. About 150,000.
Khshnoomi: Zoroastrians who follow the Ilm-e-Khshnoom ("Science of Inner Joy"), a school founded by Behramshah Shroff in the 19th century. Khshnoomis believe in reincarnation. About 20,000 in India and a few in North America. Most are Traditionalist.
Restorationists: These are Zoroastrians who believe in "restoring" the original religion of Zoroaster, without all the "traditions" that have been added to it over time. They see the Gathas (Hymns of Zoroaster) alone as being inspired of God. They disregard all later Zoroastrian sciptures. Hard to say their number, but perhaps 15% of all Zoroastrians worldwide. Perhaps more.
Zarathustrian Assembly: A small sect in southern California which is Restorationist.
Zoroastrian Assemblies of God: A small sect in the U.S. and Canada which accepts Jesus as one of the Sayoshants ("Saviors"), and also accepts the Ilm-e-Khshnoom. Believes in reincarnation.