The paper investigates the impact of off-farm income on farm technical efficiency for the Slovenian Farm Accountancy Data Network farms in the years 2004-2008. Farm stochastic frontier time-varying decay inefficiency is positively associated with total utilised agricultural areas and total labour input, and vice versa with intermediate consumption and fixed assets. We find a positive association between farm technical efficiency and the off-farm income. Farm technical efficiency has increased steadily over time, the process, which was led by the off-farm spill over effect and most efficient farms. Farm technical efficiency is also positively associated with economic farm size, while association with subsidies is mixed depending on the estimation procedure. Quantile regression confirms the positive and significant associations between farm technical efficiency and off-farm income, and between farm technical efficiency and farm economic size, as well as also the positive association between farm technical efficiency and subsidies, but the results are sensitive by quantiles.