Samuel Grimes and Benjamin Grimes, both from Bolton, Mark Rhodes of Moston and Christopher Moore of Heywood were found guilty of conspiracy to commit burglary and sentenced to nearly 20 years in jail on Friday.
The men targeted 26 different schools committing burglaries in Wakefield, Liverpool, Rossendale and multiple locations across Greater Manchester.
Greater Manchester Police said a member of the gang typically visited the school during the day and removed an alarm sensor from the main doors.
This would disable the system and ensure the alarm would not work effectively when it was set at the end of the school day.
On some occasions the gang members would even engage school office staff about potential places for their own children, in order to distract the staff while they stole the door sensors.
The gang would then return when the school was empty, breaking in through the unsecure door to steal laptops, iPads and computer equipment.
They sold the goods across the world and split the profits.
Detective Inspector Charlotte Cadden said: “This is a superb result for our officers, who have worked incredibly hard to bring this gang to justice.
“The impact their crime spree has had on these schools has been massive, and can not only be measured in financial terms.
“Obviously the cost to the various education authorities has been huge, but the impact these thefts had on the school children must also be acknowledged.
“Many of those children had irreplaceable school work saved on these devices, and that is now lost forever thanks to these men.
“Their crimes affected a huge number of children and this gang are fully deserving of the substantial custodial sentences handed out by the judge.”
Samuel Grimes was jailed for two years and eight months, Benjamin Grimes was jailed for seven years, Mark Rhodes was jailed for six years and six months and Christopher Moore was jailed for three years and four months.