Abasia (from Greek: a-, without and basis, step) is the inability to walk due to impaired muscle coordination. The term covers a spectrum of medical disorders such as:

• choreic abasia: caused by chorea of the legs
• paralytic abasia: caused by paralysis of the leg muscles
• spastic abasia: caused by spastic stiffening of the leg muscles
• trembling abasia: caused by trembling of the legs

Abasia is frequently accompanied by astasis, an inability to stand, see Astasia-abasia.