意向性（英语：Intentionality）是心灵代表或呈现事物、属性或状态的能力。简单的说，很多心理活动是关于外部世界的，意向性就是这里的“关于”。最初，“意向性”一词来自经院哲学。十九世纪哲学家、心理学家弗朗兹·布伦塔诺在他的《经验主义视角下的心理学》（德语：Psychologie vom Empirischen Standpunkte，英语：Psychology From an Empirical Standpoint）一书中将其引入了当代哲学。布伦塔诺将其定义为“心理现象”（psychical phenomena）的特征之一，由此和“物理现象”区分开。他使用了诸如“同内容的联系性”，“对物体的指向”或“内在的客观性”等表达方式。

Intentionality is a philosophical concept and is defined by the Stanford Encyclopedia of Philosophy as "the power of minds to be about, to represent, or to stand for, things, properties and states of affairs". The term refers to the ability of the mind to form representations and should not be confused with intention. The once obsolete term dates from medieval scholastic philosophy, but in more recent times it has been resurrected by Franz Brentano and adopted by Edmund Husserl. The earliest theory of intentionality is associated with St. Anselm's ontological argument for the existence of God, and with his tenets distinguishing between objects that exist in the understanding and objects that exist in reality.