Teachers have faced particular problems taking time off for the High Holy Days this year, according to their representative body.
Daniel Needlestone, chair of the Jewish Teachers Association, said the problems have been particularly bad because all the Jewish festivals fell on weekdays.
"Some people have faced major problems. It's very hard for teachers to take time off during term time and some schools say teachers are being unreasonable in asking," he said.
"Some local education authorities don't seem to have policies on religious holidays, in which case it can be entirely at the discretion of individual schools to decide."
Ronnie Fraser, director of the Academic Friends of Israel, agreed that problems with taking time off for festivals "hits the teaching profession more than any other".
He said: "Most head teachers are understanding, but this problem is becoming a bigger issue, with more and more young Jewish people going into teaching."
Retired teacher Vera Feldman, 78, from Birmingham, who campaigned for Jewish holidays with pay in 1952, said: "I worked in Bristol and negotiated to take the Yomtovim off as paid leave. Teachers need to continue to campaign for this today."
A spokesman for the Board of Deputies confirmed they had received more calls about leave issues this year, adding: "If a teacher takes a day off, and a supply teacher is required, that will often be a burden on financial and administrative resources."
Rosalind Schogger, who has worked for Brent Education Tuition Services for eight years, said she had taken Yomtovim off "with no problem", but when she requested two days' unpaid leave for Succot her request was denied. She contacted the Board, who wrote to Brent Education Department.
Mrs Schogger, from Harrow, said: "In the end I took the days off. I was worried they would take disciplinary action against me but after receiving the Board's letter, a letter from my rabbi and many emails from me, they said they would approve it as unpaid leave. It has been very stressful."
A Brent spokesman said: "Teachers are entitled to claim up to three days' paid leave during term time. Ms Schogger was granted three days leave on full pay. She requested a further four days' unpaid leave which was initially turned down. However, after consultation, Ms Schogger was granted all the leave she requested."