A religious teacher at a local Islamic school was in a classroom with his eight-year-old pupil when he molested the girl.
The 31-year-old man was jailed for eight months yesterday after pleading guilty to outraging the child's modesty.
A second molestation charge involving the same girl was considered during sentencing.
The Singaporean man cannot be named due to a gag order to protect her identity.
He was teaching in the madrasah classroom on Feb 10, 2017, when he asked the girl to stand beside him to read a passage.
He then molested the girl, who later told her mother about the incident.
Court documents did not state if other pupils were present at the time.
Deputy Public Prosecutor David Koh urged District Judge Christopher Tan to sentence the man to at least nine months' jail, saying he had abused the trust placed in him.
Madrasahs in Singapore are under the purview of the Islamic Religious Council of Singapore (Muis).
Responding to queries from The Straits Times, Muis said that the man was suspended when the incident came to light.
Its spokesman added: "Muis does not condone the abhorrent acts of the individual. The safety and welfare of our students are of paramount importance."
Offenders convicted of molesting a child below 14 years old can be jailed for up to five years and fined or caned.