The school says the retirement will be official as of 5 p.m. Thursday.
She was placed on leave after the incident. She will receive no severance package, but she qualifies for retirement benefits.
Spicuzza was assigned much of the blame by the Reynoso report for the unorganized and poorly-communicated response to protesting students November 18. Officers pepper sprayed and arrested several students protesting rising tuition costs.
The report says police and school administrators failed to properly plan for their reaction to the protest, and then didn't follow the plan they had.
The Reynoso report recommended an independent review of UC Davis Police procedures and for training for all police departments in the UC system.
A spokesman for the school says the internal investigations into the officers' actions are nearing conclusion.