"He fell behind in/on his rent."
Which preposition (in, on) is more appropriate right after "behind"?
'with' would be better still.
NOT A TEACHER.
I don't see anything wrong with using "on." Perhaps this is a matter of American English versus British English.
A Scandal and a Debt
In the new year, however, he fell behind with his rent and wrote to his landlord Captain John Hamilton...
Maine Budget Matters » Gov. LePage’s Budget Proposal is Bad for Maine Families and Workers
Families and individuals often apply for GA when they are in crises like the loss of a job, something that would cause them to fall behind in paying their rent or paying for heat.
"On the rent" here. He fell behind on his mortgage.