Acetylcholine (ACh) plays an important role in memory function and has been implicated in aging‐related dementia, in which the impairment of hippocampus‐dependent learning strongly manifests. Cholinergic neurons densely innervate the hippocampus, mediating the formation of episodic as well as semantic memory. Here, we will review recent findings on acetylcholine's modulation of memory function, with a particular focus on hippocampus‐dependent learning, and the circuits involved. In addition, we will discuss the complexity ofACh actions in memory function to better understand the physiological role ofACh in memory.This is an article for the special issue XVth International Symposium on Cholinergic Mechanisms. image