Counter Terrorism Policing North East launched an investigation after a member of the public raised concerns about posts by the 16-year-old.
He was arrested in May 2021.
The boy, who cannot be named because of his age, was summoned to appear before Westminster Youth Court, where he pleaded guilty to one offence of disseminating a terrorist publication and one offence of possessing terrorist material.
He has today been sentenced to a 12-month Referral Order.
It means trained community volunteers and a member of the youth offending team will work with him on "reparation or restitution", as well as a programme of activities to address his offending behaviour.
He was also ordered to pay costs and given a Criminal Behaviour Order lasting until the day before his 18th birthday.
Det Chief Supt Martin Snowden, head of CTP North East, said: "We would always encourage members of the public to report material of concern so it can be removed and appropriate action taken.
"We have seen before how online extremism can fuel hate and influence others, and that is true of this case.
"Through reports such as these, the work of the CTIRU and the support of online service providers, we can silence those wanting to spread hatred and protect others from the harm that takes place on online platforms."