Diets in Nigeria, across population and all income quintiles are lacking diversity and continue to include too many calories from staple foods and too few from nutritious foods such as vegetables, fruits, pulses and nuts, and some animal source-foods. In 2018, about eight out of every ten children between 6 and 23 months were fed an insufficiently diversified diet that fell short of a daily minimum. The paper therefore assessed the extent and effect of farm production diversity on farm household’s dietary diversity in the country using a cross sectional data from national representative sample of five states drawn from five geopolitical zones of Nigeria. Simpson Diversity Index, Household Dietary Diversity Score (HDDS) and regression technique were used for data analysis. Results showed a positive effect of agricultural production diversity on household dietary diversity score. Household size, sex of household head, extension service and asset ownership all exert positive and significant effect on dietary diversity of households practicing farm diversification. Effect of extreme rainfall on dietary diversity is negative and significant for households practicing agricultural production diversification. The result shows the importance of access to extension service in enhancing agricultural production diversity and strengthening dietary diversity of the farming households. The study recommends reinforcement of agricultural extension service to boost the diversity and level of agricultural production. This in turn could lead to improvement in dietary diversity and nutrition security among rural farming households. In conclusion, the importance of ownership of assets should be emphasised at implementation of agricultural development programmes for the rural farming households for advancing dietary diversity in the rural sector.