Domain Expansion (領りょう域いき展てん開かい Ryōiki Tenkai) is an extremely advanced technique and considered the pinnacle of Jujutsu Sorcery in the anime and manga series Jujutsu Kaisen. It is also an extremely difficult technique for most Jujutsu Sorcerers to pull off and as such only 7 Jujutsu Sorcerers have been able to perform this technique.

In order to perform a Domain Expansion you require the following things:
1. A large amount of cursed energy.
2. An innate cursed technique.
3. A mental landscape that reflects both your personality and your cursed technique. This is also known as a Domain.
4. The ability to construct a barrier or use barrier techniques.
5. A specific hand-sign to activate it.

A Jujutsu Sorcerer needs to combine all these elements, using cursed energy to surround themselves and their opponent in a barrier and then expand their mental landscape containing their cursed technique from the confines of their minds out into the physical world.

The result is that the user and anyone caught within the barrier of the domain expansion is transported to an alternate plane of existence comprised entirely of the sorcerer's curse technique which the caster can control at will. This most often creates the "sure hit" or "can't miss" effect where opponents will be unable to avoid the attack since their body is currently inside and touching the curse technique.

If 2 Jujutsu Sorcerers activate their domains at the same time, the more refined of the two will win out and subsume the weaker domain. Under most circumstances, using a Domain Expansion will result in a sorcerer unable to use their cursed technique for at least 24 hours.

Domain Expansions are categorized as either lethal or non-lethal. Lethal domains create the aforementioned unavoidable effects. Non-lethal Domain expansion sacrifice the sure-hit effect for some kind of utility or boon like infinite cursed energy or removing the opponent's access to their cursed technique.