Has an acyl-CoA thioesterase activity with a preference for the long chain fatty acyl-CoA thioesters hexadecanoyl-CoA/palmitoyl-CoA and tetradecanoyl-CoA/myristoyl-CoA which are the main substrates in the mitochondrial beta-oxidation pathway. . This is the function of ACOT11 (acyl-CoA thioesterase 11, ENSG00000162390).