A field experiment was conducted during summer season of 2022 at Tamil Nadu Agricultural University, Coimbatore to study the influence of millet based intercropping systems on growth and productivity of castor under irrigated situation. The experiment was laid out in randomized block design and replicated thrice. The treatment consist of nine cropping systems viz., castor + foxtail millet (1:3), castor + proso millet (1:3), castor + little millet (1:3), castor + kodo millet (1:3), paired row castor + foxtail millet (2:4), paired row castor + proso millet (2:4), paired row castor + little millet (2:4), paired row castor + kodo millet (2:4), sole castor. Experimental results revealed that the different millet based cropping systems significantly influenced growth and productivity of castor. Sole castor was recorded the highest growth, yield parameters and seed yield (20.98 q/ha). Among the millet based intercropping systems, maximum values of growth parameters viz., plant height (170.20 cm), number of branches/plant (7.90), stem girth (8.70 cm) and dry matter production (29.83 q/ha) were recorded in the paired row castor + proso millet (2:4) and it was on par with paired row castor + foxtail millet (2:4). Similarly, yield and yield attributing characters viz., number of spike/plant (28.2), number of capsule/ spike (55.8), highest length of primary branch (40.1 cm) and seed yield (20.03 q/ha) was obtained in paired row castor + proso millet (2:4) and it was comparable paired row castor + foxtail millet (2:4). The economic study revealed that the higher net return and benefit cost ratio was obtained from paired row castor + foxtail millet (2:4) (₹. 74,842.00 and 2.30) and paired row castor + proso millet (2:4) ((₹. 72,702.00 and 2.26). From this study, it was concluded that proso millet and foxtail millet were indentified to be compatible intercrops with castor for improved productivity.