Kʼinich Yoʼnal Ahk II (born December 29, 664), also known as Ruler 3, was the ajaw (king) of Piedras Negras, a Maya city in Guatemala.

Piedras Negras was extremely influential on Classic Maya society despite its small size, and K'inich Yo'nal Ahk II oversaw a flourishing city that produced high-quality art and trade goods.

[2] Still, the king seems to have lost important territory, and the influence of the city in the broader Maya world may have constricted during his reign.

Yoʼnal Ahk recorded a number of important ritual events, such as the anniversary of his accession into the kingship and a possible dance in a place called the White "Yek?"

As he was alive for a wedding on June 28, 729 according to a set of conch shells from a burial in Piedras Negras, he must have died in that year.