In anatomy, an eyestalk (known as an ommatophore) is a protrusion that extends the eye away from the body, giving the eye a better field of vision. It is a common feature in nature and frequently appears in fiction.

Eyestalks are a specialized type of tentacle. Tentacles may also have olfactory organs at their ends. Examples of creatures with olfactory tentacles include snails, the trilobite superfamily 'Asaphida', and the fly family 'Diopsidae'. In slugs and snails, these tentacles will regrow if severely damaged, and in some species, are retractable. The tentacles of aquatic snails do not regrow.

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