Magufuli, nicknamed "the bulldozer" for pushing through his policies, has won some praise from Western donors for anti-corruption drives and cutting wasteful government spending since coming to power in November.
But opponents accuse him of becoming increasingly authoritarian, undermining democracy by curbing political activity and restricting live television coverage of parliamentary sessions.
Insulting the president was made a criminal offense in Tanzania under a cybercrimes law passed last year, punishable by up to three years in jail, a fine of around $3,000, or both.
"The senior university lecturer was arraigned in court yesterday, and I think he was later released on bail," Julius Mjengi, police chief of the south-west Tanzanian town of Iringa told Reuters by telephone.
Police said the lecturer was charged with offenses under Tanzania's strict cybercrimes law. The lecturer denies the charges.
"The number of people who have been arrested across the country thus far for insulting the president has now risen to 10," Tanzanian newspaper Mwananchi said in an article on Friday.
Those who have faced trial for insulting Magufuli in recent months include students and opposition politicians.
A U.S. aid agency in March canceled nearly $500 million of funding for Tanzania partly on concerns over enforcement of the new cybercrimes law.
The U.S. government's Millennium Challenge Corporation said Tanzania has "engaged in a pattern of actions inconsistent with MCC's eligibility criteria" hence the decision to suspend its partnership with the East African nation.
(Reporting by Fumbuka Ng'wanakilala; Editing by Duncan Miriri and Hugh Lawson)