The High Court has also asked the Crime Bureau of Investigation (CBI), which is probing the case, to submit a report in the matter on December 5.
"High Court Justice Surinder Gupta today granted interim bail to them (the three trustees) till December 5," said Arshdeep Singh Cheema, who along with Sandeep Kapur, appeared for the Pinto family.
They have also been asked by the court to join the investigation whenever called by the CBI, Mr Cheema said.
"The CBI has also been asked by the high court to submit a report in this matter on December 5," said Mr Cheema.
On September 28, the High Court had stayed the arrest of the three trustees of the Ryan group, who had sought anticipatory bail in this case.
Mr Pinto and his parents had approached the High Court on September 16, seeking anticipatory bail in connection with the student's killing.
Class 2 student Pradyuman Thakur was found with his throat slit in a school washroom on September 8. School bus conductor Ashok Kumar was arrested in connection with the crime.
There was nation-wide outrage over the child's killing and allegations were leveled against the school management also.
The Haryana government had earlier recommended a CBI probe in the matter. The premier investigating agency took over the case on September 22.