They are all charged with seeking to carry out "acts of terrorism, or assisting others to commit such acts", between July and October this year.
The men, all from London, are Nyall Hamlett, 24; Tarik Hassane, 21; Suhaib Majeed, 20; and 21-year-old Momen Motasim, Scotland Yard said in a statement.
Details of the charges included taking "an oath of allegiance to the group IS (Islamic State)", listed as a terrorist organisation.
Others included downloading, circulating, discussing and deciding to act on a fatwa, or religious edict, by IS spokesman Abu Mohamed al-Adnani.
They also allegedly had "extremist jihadi material" and a picture of two London police officers.
A fifth man, Nathan Cuffy, 25, also from London, was charged with a firearms offence.
All five were due to appear later today at a London court.
Two men aged 21 and 20, arrested on October 7 as part of the investigation were released from custody on Monday, while a third was released today after prosecutors advised there was insufficient evidence to charge him.
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