This manual has been written to accompany the 12-hour Mental Health First Aid for the Older Person course. The course is designed for members of the public to learn how to assist an older person who is developing a mental health problem, has a worsening of an existing mental health problem or is in a mental health crisis. The giving of mental health first aid is most relevant in situations when it is first becoming apparent to others that an older person is developing a mental health problem. However, the manual may also provide some useful information on how to assist an older person who has a history of a mental illness or longer-term mental health problems. For the purpose of this manual, ‘older person’ refers to someone who is over the age of 65 years, or 50 years for a person who is of Aboriginal or Torres Strait Islander descent.