This study investigated the effects of using Socratic questioning to enhance students' critical thinking (CT) skills in asynchronous discussion forums (ADF) in university-level distance learning courses. The research effort empirically examined two coherent subjects: (a) the efficacy of teaching and modeling Socratic questioning for developing students' CT skills in ADF and (b) the persistence of students' CT skills following the teaching and modeling of Socratic questioning in the ADF. The results indicate (a) teaching and modeling of Socratic questioning helped students demonstrate a higher level of CT skills and (b) students maintained their CT skills after exposure to and modeling of Socratic questioning in the ADF.