Visualizing hypothesis tests in multivariate linear models: the heplots package for R Linear hypotheses are considered for linear regression models with multivariate response. Hy-poth-eses-error (HE) plots are used as visual tools for such hypotheses testing. These plots are implemented in two and three dimensions in the heplots package for the statistical software R system. The authors describe the use of heplots considering real life data examples including one-way and two-way MANOVA, multivariate multiple regression and multivariate analysis of covariance (MANCOVA).