The onion plant is attacked by several insect pests. The Onion thrips is one of the insect pests that feeds directly on leaves, distort the bulbs and causing yield loss >50%.Field experiment was conducted at Koga Irrigation Scheme Site in west Gojjam administrative zone, Under irrigation season of 2019/2020 to evaluate selected botanicals and synthetic insecticides with varieties for the management of onion thrips. Treatment combinations were two onion varieties (Adama red and Bombay red), two selected botanicals i.e., jimson weed (Datura Stramonium), neem (Azadirachta indica) leaf powder and two synthetic insecticides i.e., dimethaote 40% EC and Karate 5% EC. The experiment was laid out in randomized complete block design in factorial arrangement with three replications. All the Data (population of thrips/plant, mortality percentage, infestation ,leaf damage ,Plant height, number of leaves per plant , Biomass weight in kg ha-1 , marketable yield in kg ha-1 and total yield ha-1)were subjected to analysis of variance (ANOVA) using the PROC-GLM procedure of SAS version 9.1software. Highest mortality percentage (65%) with least population of thrips/plant (1.66) was recorded on Adama red treated with Datura stramonium. Lowest mortality (24.43%) with high population of thrips/plant (4.00) was recorded on Bombay red treated with Karate 5% EC. The combinations of onion varieties with selected botanicals and synthetic insecticides showed statistically significant on number of thrips, yield and yield components. Up to 100% infestation and the highest leaf damage (>75%) were recorded on unsprayed varieties of Adama red. Bombay red variety treated with Karate 5% EC gave highest mortality percentage (53.3%), Plant height (13.2 cm), number of leaves per plant (43.03), biomass weight in kg ha- 1(9166) , marketable yield in kg ha-1 (8600) and total yield ha-1 (9441) followed by Adama red treated with Datura stramonium with Plant height (12.6cm), number of leaves per plant (35.5), biomass weight in kg ha-1(8609),marketable yield in kg ha-1 (7350) and total yield ha-1 (9025).. In conclusion, as the partial budget analysis revealed that the highest net benefit with low cost of production was obtained in response to the application of Karate 5% EC 1l ha-1 and Bombay red variety was effective for producing the crop in the study area. The current results showed insecticides and varieties of onion may play in effectively managing onion thrips. However, further research is needed for sustainable and cost effective management of the insect under different agro-ecological settings.