Tinodon is an extinct genus of mammal alive 155–140.2 million years ago (Oxfordian-Berriasian) which has been found in the Morrison Formation (United States), the Alcobaça Formation (Portugal) and the Lulworth Formation (England). It is of uncertain affinities, being most recently recovered as closer to therians than eutriconodonts but less so than allotherians. Two species are known: T. bellus ( Marsh, 1879 ) and T. micron ( Ensom & Sigogneau-Russell, 2000 ).