Brazilian Jiu-Jitsu is primarily a ground-fighting art. Most techniques involve both fighters on the mat. There is a heavy emphasis on positional strategy, which is about which fighter is on top, and where each person's legs are. Positions are stable situations, from which a large variety of techniques are available to both fighters.

• Guard: The person applying the guard is on the bottom with his back on the ground; his legs are wrapped around his opponent's hips (who is said to be "in the guard").
• Side control: Chest-on-chest but without the legs being entangled.
• Mount: On top of his opponent (who "is mounted"), sitting on his chest, with one leg on either side of his torso.
• Back mount: Behind his opponent, with his feet hooked around his opponent's hips and upper thighs.

Specific techniques taught are designed either to improve one's position (for example, to "pass the guard", by going from being "in the guard" to getting around the opponent's legs, resulting in side control); or else as a finishing submissions. Most submissions are either chokes (cutting off the blood supply to the brain) or arm locks (hyperextending the elbow, or twisting the shoulder).

Belt ranks start at white belt, and progress through blue, purple, brown, and then black. It generally takes about 2-3 years of training multiple times per week to be promoted to the next belt rank. However, there is no formal rank test. Instead, rank is about the ability to apply jiu-jitsu techniques in a competitive match. A student generally needs to be able to reliably defeat most other students at a given rank in order to be promoted to the next rank.

Given the jiu-jitsu roots, and the interest in competition, occasionally related techniques are taught. In each case, other specific martial arts focus on these sets of techniques more than BJJ, and they generally just receive passing mention and rare practice in BJJ training. For example, takedowns tend to be similar to Judo and western wrestling; leg locks (such as in Sambo) are not encouraged but sometimes allowed. Some schools teach street self-defense or weapon defense as well; this instruction tends to be much more like old-style Japanese jiu-jitsu with partner practice, and rarely impacts the day-to-day grappling training. Also, many dedicated BJJ students are also interested in MMA competition, and attempt to practice their techniques without a gi, and sometimes with adding striking from boxing or Muay Thai.