Eggertsbók (Reykjavík, Stofnun Árna Magnússonar, AM 556a-b 4to) is a fragmentary Icelandic manuscript, produced in the last quarter of the fifteenth century; its provenance is currently unknown. The manuscript now survives bound in two separate parts, now known as 'a' and 'b'. However, it is likely that originally the 'b' section came first. The manuscript is named after its earliest clearly identifiable owner, Eggert Hannesson (c. 1515–83).