This article deals with the transcrystallization of polypropylene on untreated, MAH-polypropylene grafted, and alkali treated jute fibers due to isothermal as well as non-isothermal crystallization conditions. In both cases, TCL-thickness as well as TCL growth initiation temperature were dependent on fiber treatment. The chosen T-C in isothermal conditions was of great significance on TCL growth rate. The experimental data were successfully fitted by using an Arrhenius-type relationship.