Allan R. Wagner (6 January 1934 - 28 September 2018) was an American experimental psychologist and learning theorist, whose work focused upon the basic determinants of associative learning and habituation. He co-authored the influential Rescorla–Wagner model of Pavlovian conditioning (1972) as well as the Standard Operating Procedures or "Sometimes Opponent Process" (SOP) theory of associative learning (1981), the Affective Extension of SOP (AESOP, 1989) and the Replaced Elements Model (REM) of configural representation (2001, 2008). His research involved extensive study of the conditioned eyeblink response of the rabbit, of which he was one of the initial investigators (1964).