Disclosed are a method and system for providing user notification when personal information is used in a speech controller. A method of providing user notification may include receiving information monitored for reference to personal information in a process of processing a user's query in a voice service, storing a personal information utilization history for each user and for each service based on the monitored information, determining the suitability of the reference to the personal information based on the monitored information, determining whether the personal information is included in a response when generating the response to the user's query, generating and providing guide information indicating that the personal information is included in the response if the personal information is included in the response, and providing the response to the user's query based on feedback from the user for the guide information.