diff --git a/.travis.yml b/.travis.yml
index ef787d5..7e36da7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -23,7 +23,7 @@ install:
 
   # Install R packages
   - ./travis-tool.sh r_binary_install knitr png
-  - ./travis-tool.sh r_install        ggplot2 dplyr tidyr pryr stringr
+  - ./travis-tool.sh r_install        ggplot2 dplyr tidyr pryr stringr htmlwidgets htmltools
   - ./travis-tool.sh github_package   hadley/bookdown garrettgman/DSR hadley/readr gaborcsardi/rcorpora hadley/stringr
 
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