The study examined the differential efficacy of Verbal Self-instructional (VSI) training on tribal and non-tribal low achieving school children who follow either internal locus of control (ILC) or external locus of control (ELC) and the maintenance of training effects over time and generalisation across different tasks and settings. Type of sub-culture (Tribal vs. Non-tribal) has been crossed with the type of locus of control (Internal vs. External) to produce four VSI treatment groups with 20 Ss per cell. The treatment groups received two months training and were retested after training for posttest and follow-up data. The VSI training has been very much beneficial to the non-tribal children and those having ILC but failed to yield desirable results for the tribal and children with ELC. The VSI effects were maintained for a period of four months and evidenced clear generalisation effects to a variety of task situations and different settings. The importance of child variables as active moderators of VSI treatment efficacy has been discussed.