Described as new are 12 species of snail-killing flies (Diptera: Sciomyzidae) of the genus Dictya Meigen from the Americas: D. ahbellae, D. aprilae, D. coryi, D. dunnei, D. emrehorum, D. garlandi, D. gibbsi, D. heyjimi, D. jemae, D. jofusi, D. malloyi, and D. youngi. Specimens representing these species were discovered among more than 5600 specimens of Dictya examined by the author between 2007 and 2022. The 12 new species bring to 56 the number of described, valid species in the genus Dictya. Also identified and described for the first time is the female of D. praecipua Orth.