Spasticity is a phenomenon regularly encountered in neurorehabilitation but also in regular clinical practice. Its clinical assessment must be detailed and associated with an evaluation of the functional aspect in order to set up therapeutic strategies according to personalized goals. Indeed, appropriate management consists of treating the functional discomfort, pain and preventing irreversible long-term effects. Nevertheless, spasticity can sometimes prove useful in palliating motor deficiency and allowing an activity such as walking, it then does not require treatment that could result in a deterioration of such function. The aim of this article is to define spasticity, develop the means of clinical and functional evaluation and outline the different therapeutic approaches.