心理学家（Psychologist），研究心理学之学者。

最早起源于哲学，十九世纪从哲学中分离出来成为一门独立的研究学科。对人类自我思维、行为方式剖析，研究人类怎样感知外界信息和怎样进行信息内化处理的心理和行为的规律的科学。

一位心理学家常常需要具备自然科学和社会科学两方面的知识和素养。在自然科学方面，他需要了解神经科学、生理学、生物化学、生态学、物理学等；在社会科学方面，他需要懂得社会学、人类学、语言学等。

A psychologist is a professional who evaluates and studies behavior and mental processes (see also psychology). Typically, psychologists must have completed a university degree in psychology, which is a master's degree in some countries and a doctorate in others (e.g., United States, Canada and United Kingdom). This definition of psychologist is non-exclusive; in most jurisdictions, members of other professions (such as counselors and psychiatrists) can also evaluate, diagnose, treat, and study mental processes. Some psychologists, such as clinical and counseling psychologists, provide mental health care, and some psychologists, such as social or organizational psychologists conduct research and provide consultation services.