This study examines unionization efforts among contingent faculty members, who now account for the majority of the academic workforce. Drawing on data from the National Labor Relations Board (NLRB) and other sources, this article uses an event history analysis to identify factors associated with efforts to establish a contingent faculty union at private, 4-year institutions. Even after accounting for other state and institution characteristics, this study finds increased odds of contingent faculty unionization at institutions located in states where the legislature is more liberal and where more contingent faculty union certification elections have been held previously.