Canonical variates analysis was used to compare the effects of fertilization on the concentrations of five mineral elements (N, P, K, Ca, and Mg) in young shoot tissues of six tundra plant species of three different growth forms. There were two specific objectives: (i) to determine whether it was possible to describe meaningful dose–response relationships in a multivariate response to fertilization, and (ii) to determine the multivariate effect of N plus P fertilization in comparison with the effects of N or P added alone. The results showed that low levels of N–P–K fertilization caused a shift in multivariate nutrient content that was intermediate between the control values and the shift caused by high fertilization, and in the same direction as the latter. In a June harvest, the effect of N plus P fertilization was very similar to the effect of N fertilization alone. However, in August the N plus P effect was dominated by the response to P alone. In all of the analyses, the fundamental similarities and differences among unfertilized plants of each species and growth form were maintained under fertilization.