Mrs Judd, 56, former education editor of the Independent, takes over from Bob Doe who resigned due to ill-health.
She joined The TES in 2001 as associate editor with particular responsibility for the news and analysis sections.
Before her 11-year spell on the Independent, she worked for the Observer, the Times Higher Educational Supplement and the Birmingham Post and Mail.
During her time on the Independent, Mrs Judd claimed one of the biggest education scoops of recent years when she revealed the admission of former chief inspector Chris Woodhead that teacher-student relationships could be "educative".
A history graduate of St Anne's college, Oxford, Mrs Judd was a governor at an Oxfordshire middle school which her son and daughter attended.
She can claim a special insight into the paper's religious coverage as her husband Peter is the dean of Chelmsford Cathedral.
Mrs Judd said: "I am delighted to have the chance of editing The TES and building on the work done by Bob Doe. The TES is a great newspaper with a lively community of readers who keep in touch with us and with each other, in the paper and on our website. We look forward to developing it to support and entertain them even more."
Bob Doe, who joined the paper in 1973 and had been editor since 2001, said:
"I am leaving with regret but with complete confidence in The TES team to carry the paper forward. Judith Judd will be an outstanding editor."