Nonparametric Tests for Random Effects in Linear and Nonlinear Mixed-Effects Models R package TestREnlme version 0.1.0 Provides nonparametric permutation tests for testing all or any subset of random effects in linear and nonlinear mixed-effects models, without requiring normality or other distributional assumptions on random effects or errors. Three distribution-free variance-component estimators are implemented: Variance Least Squares ('VLS'), Method of Moments ('MM'), and Method of Moments with First-Order Approximation ('MMF'). A permutation procedure is used to obtain finite-sample p-values. Plotting functions support data exploration, model evaluation, and communication of results. Methods are described in Uwimpuhwe, Drikvandi, and Blozis (2026) <doi:10.1002/sim.70605>. Software Depends: R (>= 4.1.0) Imports: nlme (>= 3.1-150), Matrix (>= 1.3-0), MASS (>= 7.3-54), mgsub (>= 1.7.3), matrixcalc (>= 1.0-5), nls.multstart (>= 2.0.0), ggplot2 (>= 3.3.5), expm (>= 0.999-6), withr (>= 3.0.2), stats, utils, rlang Suggests: knitr, rmarkdown, ggpubr (>= 0.4.0), testthat (>= 3.0.0), reshape2 (>= 1.4.4) Germaine Uwimpuhwe <germaine.uwimpuhwe@durham.ac.uk> Comprehensive R Archive Network (CRAN) Germaine Uwimpuhwe [aut, cre], Reza Drikvandi [aut], Shelley A. Blozis [aut] GPL (>= 3) 2026-07-03 application/tgz https://CRAN.R-project.org/package=TestREnlme doi:10.32614/CRAN.package.TestREnlme