The purpose of the article is to determine development gaps and critical points in the system of business – education collaboration in R&D investment using MAR-splines. The study attempts to confirm hypotheses about the impact of business – education collaboration in R&D investment on the sustainable development, and, in turn, the influence of chosen factors on the level of cooperation of business and education in R&D investment taking into account development gaps and critical points. These factors include the values of gross domestic expenditure on R&D spent by the business enterprise sector and by the higher education sector, and the level of the informal economy. The study is based on the sample of the 10 countries leading the ranking of Sustainable Development Index for 2011-2018 (time limits are set due to the availability of all studied indicators in the statistical databases of the World Bank, UNDESA, OECD and WIPO). Critical points and knots are determined using MAR-splines and two-way median-spline plots in STATA software. It has been proven that the business – education collaboration in R&D investment contributes to increasing the level of sustainable development if the value of this indicator is in the range of critical points from 62.04 to 68.96 (1% growth increases the estimate of sustainable development by 0.7%). In turn, development gaps and critical points have also been found for factors influencing the level of business-education R&D collaboration.