Llyn Bochlwyd (Welsh pronunciation: [ɬɨ̞n bɔχluːɨ̯d, ɬɪn bɔχlʊi̯d]) is a lake in Snowdonia, Wales, in Conwy County Borough.

It lies in Cwm Bochlwyd, near Llyn Ogwen in the Glyderau mountain range.

According to a local legend, this is where an old grey stag, fleeing a hunter, miraculously escaped by leaping from a great height into the lake and swimming to safety while holding its grey cheeks above the surface, in order to breathe.

In 2018 the broadcaster Tudur Owen cited the name change as an example of "erasing history".

[4] In 2023 the Eryri National Park Authority voted to use a standardised list of names for its lakes, all of which are in Welsh only.