Roger Caffrey, 70, was found guilty of three counts of rape and 12 counts of indecent assault in Nottinghamshire from 1978 to 1994.
One ex-pupil was raped six times by Caffrey at his home during a "campaign of rape", Nottingham Crown Court heard.
A number of offences against his seven victims took place during lesson time.
Caffrey was cleared of two charges of indecent assault following a three-week trial.
Police began investigating him after a victim, who said she was raped when she was nine years old, contacted officers in December 2012.
Nottinghamshire Police said all but one of the offences took place when Caffrey was deputy head teacher at Northgate Primary School in Nottingham - now the Djanogly Northgate Academy - from 1978 to 1984.
Caffrey, of Sandesquoy, Tankerness, Orkney, taught at 10 schools in the county in a career spanning more than three decades.
Pupils "no older than 11 years of age" were touched while they read aloud in class, or when they were in a store cupboard in the classroom, the court heard. Two victims were raped at Caffrey's home.
One of the rape victims went to the police 22 years ago but no charges were brought due to a lack of evidence, the court heard.
She was contacted in 2013 following the start of the investigation into Caffrey, but the original documents into the 1994 case had been lost.
Michael Evans, defending Caffrey, said: "He was a teacher for a number of years and, outside of these offences, a very good teacher."
Judge Timothy Spencer QC said: "You deliberately targeted these girls, you calculated that they were ripe for this sort of abuse and you calculated that they would not tell.
"Their classroom, their school, should have been a place where they felt safe and secure. They must have felt anything but."
Det Con Rob Smith, of Nottinghamshire Police, added: "Caffrey believed that he would be able to put his past behind him, but...it has been shown that the passage of time is no hindrance to justice taking its course."

The plans include a new multi-story car park and knocking down the 1937 arrivals building.
The building, which has already lost two floors due to safety concerns, has been called "unsafe" by airport bosses.
But Christopher Scholefield, from Save Jersey's Heritage, said plans to demolish the Art Deco terminal would be a loss to the island.
"Why is it that the interesting, genuine, historical, architectural artefact has to be knocked down in order to replace it on virtually the same footprint?
"If we ended up with what they're going to build... it won't be horrible, but we'll have something that's not genuine anymore."
Group chief executive officer of Jersey's airport and harbours, Doug Bannister, said: "It's actually not so original because it's been added to year after year... over the decades.
"It's an obstacle and what that means is it's too big and too close to the runway. It's currently unsafe."
A former deputy head teacher has been jailed for more than 17 years for raping and touching young girls - including one aged nine.
[NEXT_CONCEPT]
Designs for redeveloping an airport "remove" its Art Deco past, a heritage campaigner has said.