Tef crop production and productivity are influenced by cultural practices such as appropriate fertilizer application rates, right sowing dates, effective weed and pest control. However, in the, Adet district, these practices are not consistently implemented, resulting in post-harvest losses due to seed shattering. This issue is exacerbated by blanket recommendations for nitrogen fertilizer application rates and improper sowing dates for tef in the study area. This study aimed to assess the effects of sowing dates and nitrogen application rates on grain yield and yield components of tef varieties during the 2023 cropping season at the Adet Agricultural Research Centre. A factorial randomized complete block design (RCBD) was employed, incorporating three factors with three replications over one year. The main factors included three sowing dates ,which is first sowing was practiced on July 5 (spaced 10 days apart), two varieties (Quncho & Estub), and three different nitrogen levels (46 kg N ha⁻¹ (N1), 69 kg N ha⁻¹ (N2), and 92 kg N ha⁻¹ (N3)). The results indicated that delaying the sowing date until late July, combined with an increased nitrogen rate, significantly enhanced grain yield, 1000-grain weight, harvest index (HI), biomass (BM), and reduced the days to 50% heading and maturity for both varieties. Overall, the study concluded that sowing in late July with an application of N3 (92 kg/ha) improved yield and yield components for both tef varieties. Furthermore, grain yield of tef showed a significant positive correlation with dry biomass yield (0.74) and harvest index (0.85). Data on yield and yield components were collected and analysed using SAS version 9.4. The interaction between sowing date, variety, and nitrogen rates significantly affected days to heading and lodging percentage; thus, applying N3 (92kg Nha -1 and S3 (July 25) is recommended for the study area and the highest net benefit of Birr 92,533.2 ha⁻¹ and highest grain yield (1.35 tons per ha- 1 ) was observed when 92 kg ha⁻¹ of nitrogen (N) was applied during the third sowing. Given that this study was conducted at a single location over one year, it would be beneficial to repeat this experiment across multiple locations and seasons to develop more reliable recommendations.