Beornnoth of Towcester (died March 899) was the Mercian ealdorman of Tofeceaster (Towcester) during the late 9th century AD. He ruled over the lands at the very edge of Saxon Mercia, bordered by the Danelaw to the north, and he defended his fields and villages against the attacks of Sigurd Thorsson's men during the 890s despite his advanced age and his lameness. Beornnoth was friends with Uhtred of Bebbanburg and the father of Beorhtsige of Towcester, and he was a staunch loyalist of Mercia, opposing West Saxon overlordship and supporting Lord Aethelred of Mercia's decision to garrison Gloucester against an attack which never came. He died of illness in March 899, with Uhtred and his son at his side.