We live in a complex visual environment. Not all sensory input can be processed at the same time. Attention determines which subset of input is perceived, remembered and acted upon. But what determines which locations or objects are likely to be attended? In this talk I present evidence that implicit learning, or learning acquired without explicit awareness, is a major driver of spatial attention. I discuss unique characteristics of implicitly learned attention, dissociating it from goal-driven attention. I propose that much like human memory, the attention system can be divided into procedural and declarative components. Implicit learning modulates the procedural component of attention.