The man, 73, was first investigated when a complainant came forward to disclose past sexual abuse and police said further investigation led to additional victims.
The man taught Sunday school in areas of west Ottawa including his hometown of Fitzroy Harbour, West Carleton and Kanata.
The charges range from sexual assault, invitation to sexual touching, sexual interference, sexual exploitation, uttering threats and a variety of weapons offences.
The man was arrested on Oct. 19 and appeared in court Oct. 22. He remains in custody until his next court appearance Wednesday when additional charges are expected, police said.
Anyone with information is asked to contact Ottawa police at 613-236-1222, ext. 5944 or Crime Stoppers at 613-233-8477.