REBT stands for Rational Emotive Behavior Therapy. It was developed by psychologist Albert Ellis in the '50s. REBT rests on the premise that our thoughts, beliefs, and interpretations about events and situations greatly influence our feelings and behaviors.
The main goal of REBT is to help you identify and change irrational/false beliefs and thought patterns which are contributing to your emotional distress and maladaptive behaviors. Through REBT you learn that it's not the events themselves that directly cause your emotional reactions, but rather your thoughts and of those events.
REBT operates with an ABC model, whereby A stands for an activating event, B represents the beliefs and interpretations that you have about an event, and C refers to the emotional and behavioral consequences which result from those beliefs. If I use REBT therapy with you, I will help you identify and challenge irrational beliefs (such as absolutist thinking, catastrophizing, demandingness) and help you replace them with more rational and adaptive thoughts instead.
REBT uses various techniques to facilitate this process, including disputing irrational beliefs, reframing perspectives, using humor and rational arguments, and encouraging you to actively engage in behavioral and cognitive restructuring.