The Guardian temperament is one of four temperaments defined by David Keirsey. Correlating with the SJ (sensing–judging) Myers-Briggs types, the Guardian temperament comprises the following role variants (listed with their corresponding Myers-Briggs types): Inspector (ISTJ), Protector (ISFJ), Provider (ESFJ), and Supervisor (ESTJ).
Guardians are concrete in communicating and cooperative in pursuing their goals. Their greatest strength is logistics. Their most developed intelligence role is either that of the Conservator (Protectors and Providers) or the Administrator (Inspector and Supervisor).
As the security-seeking temperament, Guardians are practical and frugal types. They "share certain core values, among them the belief in a strong work ethic, the need for people and institutions to be responsible, the importance of following the rules and of serving one's community." Guardians value experience, and they seek a tangible return on their investments. Believing in common sense, they are not attracted to idle speculation. They are the glue of civilization, maintaining and nurturing institutions that have been established by the dint of hard work. They tend to be conventional and cooperative in their work, wanting to make sure everybody gets what they deserve, no more and no less. They follow the rules and conventions of their cohort or group and expect others to as well.
Interests: In their education and careers, Guardians' primary interest is business and commerce, with an eye toward practical applications in managing materiel. They are preoccupied with maintaining the morality of their group.
Orientation: Guardians have a strong sense of duty. They forgo the pleasures of the moment to prepare for unseen eventualities. They regard past events with a sense of resignation. They guard against the corruption of outside influences, and look to past experiences to guide their present choices.
Self-image: The Guardians' self-esteem is based on their dependability; their self-respect on their beneficence; and their self-confidence on their respectability.
Values: Guardians are concerned about the well-being of people and institutions that they hold dear. They trust authority and seek security. They strive for a sense of belonging and want to be appreciated for their contributions. They aspire to become executives, whether by managing their own households or by running a multinational corporation.
Social roles: In romantic relationships, Guardians regard themselves as helpmates, working together with their spouse to establish a secure home. As parents, they focus on raising their children to become productive and law-abiding citizens. In business and social situations, they are stabilizers, establishing procedures and ensuring that the material needs of the group are met.
Guardians often experience stress when rules, expectations, and structure are unclear, or when those around them do not act according to established norms. The extraverted (expressive) types—Providers and Supervisors—may respond by becoming critical of others. The introverted (attentive) types—Protectors and Inspectors—may take on the burden of trying to correct the perceived faults in the system themselves, resulting in overwork and burnout. Guardians also experience stress when the results of their hard work go unnoticed or unappreciated. 
Traits in common with other temperaments
Keirsey identified the following traits of the Guardian temperament:
- Concrete in communicating (like Artisans)
Guardians focus on facts. They are concerned about practical needs like providing goods and services that help society function smoothly.
- Cooperative in pursuing their goals (like Idealists)
Guardians value teamwork. They are committed to preserving established social institutions. Cautious toward change, Guardians work within the system to ensure that all contingencies are considered.
- "Keirsey.com Portrait of the Guardian". Retrieved 2008-05-03.
- Tieger, Paul D.; Barbara Barron-Tieger (1999). The Art of SpeedReading People. New York, NY: Little, Brown and Company. p. 66. ISBN 978-0-316-84518-2.
- Keirsey, David (1998). Please Understand Me II: Temperament, Character, Intelligence. Del Mar, CA: Prometheus Nemesis Book Company. ISBN 1-885705-02-6.
- Berens, Linda V. et al. (2001). Quick Guide to the 16 Personality Types in Organizations. Huntington Beach, CA: Telos Publications. pp. 15–21. ISBN 0-9712144-1-7.