Introduced by Sprenkle, Blow & Dickey (1999), common factors in marriage and family therapy (MFT) have been discussed over the past two decades. Although the MFT common factors literature has grown, there are misconceptions and disagreements about their role in theory, practice, research, and training. This content analysis examined the contributions of the common factors paradigm to MFT theory, practice, research, and training over the past 20 years. We identified 37 scholarly works including peer‐reviewed journal articles, books, and chapters. Using mixed methods content analysis, we analyze and synthesize the contributions of this literature in terms of theoretical development about therapeutic effectiveness in MFT, MFT training, research, and practice. We provide commentary on the substantive contributions that the common factors paradigm has made to these areas, and we discuss the implications and limitations of the common factors literature, and provide recommendations for moving common factors research forward.