Armed groups carrying out kidnapping for ransom have been blamed for raids on schools and universities in northern Nigeria in recent months, abducting more than 700 students since December.
Police officials say the most recent attack took place at Salihu Tanko Islamic school about 3pm on Sunday.
Abubakar Tegina, the school’s owner who lives nearby, told Reuters he witnessed the attack.
"I personally saw between 20 and 25 motorcycles with heavily armed people. They entered the school and went away with about 150 or more of the students," he said.
"We can't be exact because most of them have not reported to the school."
There are about 300 children who attend the school, aged between seven and 15.
A spokesman for Niger's state police said in a statement that gunmen on motorcycles attacked Tegina town.
He said the attackers were "shooting indiscriminately and abducted a yet to be ascertained number of children at Salihu Tanko Islamic school".
One person was shot dead during the attack and a second person was seriously injured, the state governor's spokeswoman said.
She said 11 of the children taken were released by the gunmen because they were "too small and couldn't walk". A group of bus passengers were also abducted, she said.
Sunday's attack in Niger is the latest in a series of mass abductions in Nigerian schools by armed gangs who collect money for ransom.
It comes just one day after the release of the remaining 14 students of a group abducted in April from a university in neighbouring Kaduna state.
The worst incident this year occurred at the Government Girls Secondary School Jangebe in February, when 279 girls were abducted and later released.
Most students kidnapped in recent months have been taken from boarding schools and many schools have been forced to close due to the frequent incidents.
In February, more than 300 schoolgirls were kidnapped by unidentified gunmen who were believed to be holding some of them in a forest in northwest Nigeria.
It was the second kidnapping in little over a week in a region increasingly targeted by militants and criminal gangs who usually ask for a ransom. There was no immediate claim of responsibility.