Albertus Frederik Johannes Klijn (17 April 1923 – 30 May 2012) was a Dutch scholar of the New Testament and early Judaism and Christianity at the Rijksuniversiteit Groningen.

He was best known for his introductory work on the New Testament, and then later for his publications on early Christian apocryphal literature.

Klijn studied theology at Rijksuniversiteit Utrecht, and submitted his doctoral dissertation in 1949 on the "Western" Text of the Gospels and Acts.

In 1967 Klijn was appointed professor of early Christian literature and interpretation of the New Testament at the Rijksuniversiteit Groningen.

It was at Groningen that he began to specialize in second-temple Jewish pseudepigrapha and in early Christian literature.