Structural Equation Model Effect Analysis and Visualization R package semEffect version 1.2.3 Provides standardized effect decomposition (direct, indirect, and total effects) for three major structural equation modeling frameworks: 'lavaan', 'piecewiseSEM', and 'plspm'. Automatically handles zero-effect variables, generates publication-ready 'ggplot2' visualizations, and returns both wide-format and long-format effect tables. Supports effect filtering, multi-model object inputs, and customizable visualization parameters. For a general overview of the methods used in this package, see Rosseel (2012) <doi:10.18637/jss.v048.i02> and Lefcheck (2016) <doi:10.1111/2041-210X.12512>. Software Depends: R (>= 4.4.0) Imports: lavaan, piecewiseSEM, plspm, ggplot2, tidyr, dplyr, utils, checkmate, RColorBrewer Suggests: testthat Weiping Mei <meiweipingg@163.com> Comprehensive R Archive Network (CRAN) Weiping Mei [aut, cre] (ORCID: <https://orcid.org/0000-0001-6400-9862>) GPL-3 2025-07-04 application/tgz https://CRAN.R-project.org/package=semEffect doi:10.32614/CRAN.package.semEffect