Kay Lynnette Sorg, 54, of Oakland is being held in Santa Rita jail in Dublin in lieu of $150,000 bail.
Sorg appeared in Alameda County Superior Court to hear the charges she faces lewd act upon a child, two counts of oral copulation of a child under 16 and penetration by a foreign object of a child under 16.
The charges involve her relationship with a former middle school student.
Sorg's former student, who was between 14 and 17 at the time, contacted the Albany Unified School District about the relationship last October, said Albany Detective Sgt. Tom Dolter.
The woman told police she was concerned about Sorg being around children, Dolter said. It's not clear why she waited so long before coming forward.
Police say the two were involved in a relationship between December 1990 and 1994. No force was involved, he said.
The school district contacted police, who launched a six-month investigation. Dolter said there was nothing to indicate there are other possible victims.
Sorg, a science teacher, has taught in the Albany schools for about 25 years.
In 1996, she won a "Join Hands Life Science" award from the Join Hands organization, a nonprofit group that brings together science educators, consumers and students to improve science education.
the relationship did not begin until 1990, when the student was a freshman at Albany High.
The sex crimes took place at Sorg's home, the school and other locations around the Bay Area, police said.
Albany police arrested Sorg on Tuesday morning at her home in the 6900 block of Buckingham Boulevard in the Oakland hills.
Immediately following her arrest, police served search warrants at her home and at the school, uncovering evidence related to the case. Police did not elaborate on what they found.
A person who answered the phone earlier this week at a listing for Sorg would not comment on the case. Albany Superintendent Willie Wong has also declined comment because the district considers it a "personnel matter."
The charges were filed under a section of the penal code that allows a criminal complaint to be filed within a year after crimes are reported to law enforcement. There must be independent evidence corroborating the allegation for such a filing.