This chapter covers the broad subject “grain yield genotype by environment interaction and related traits relationships.” The analysis can have diverse objectives, and the subject is complex, involving many data strata, variables, and relationships between all of them. What can you find and not find in this chapter? In this chapter, you will not find a step-by-step guide about data analysis, you will not find theoretical details, and you will not find an exhaustive list of publications. On the contrary, you will find a short list of publications related to the subject, some considerations to take into account before starting the analysis, short codes in R and SAS to do the analysis as well as references to the libraries and procedures, and short interpretation of the results of using some of the methodologies on a real data set, highlighting the main aspects. I intend to introduce the reader to the statistical analysis of the subject, and the methodologies available to do it. The chapter is biased by personal view of the problem and, like in many contracts, it is important to read the fine print amid so much text.