This paper is on the analysis of human capital investment and labour productivity in a situation of a rising incidence of poverty in Nigeria on a sectoral basis between 1986 and 2019. Adopting the Autoregressive Distributive Lag (ARDL) technique, three sectors were considered in the analysis: the agricultural, industrial and service sectors. Key in the results of the study is in two folds. In the first case, there is a direct positive effect of human capital investment on labour productivity, and a direct negative impact of poverty on labour productivity across the three sectors. In the second case, poverty decreases the contribution of human capital investment to labour productivity growth in the agricultural and industrial sectors in the short run only. But there is insufficient evidence on this in the service sector.