diff --git a/NEWS.md b/NEWS.md
index 261ea020d6..a401407a3c 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -472,7 +472,7 @@
 
 - added a helper function `all_rcpp_labels()`, which is simply `all_labels(engine == 'Rcpp')` and can be used to extract all chunk labels of Rcpp chunks
 
-- added a new engine named `sql` that uses the **DBI** package to execute SQL queries, and optionally assign the result to a variable in the **knitr** session; see http://rmarkdown.rstudio.com/authoring_knitr_engines.html for details (#1241)
+- added a new engine named `sql` that uses the **DBI** package to execute SQL queries, and optionally assign the result to a variable in the **knitr** session; see https://rmarkdown.rstudio.com/authoring_knitr_engines.html for details (#1241)
 
 - `fig.keep` now accepts numeric values to index low-level plots to keep (#1265)
 
@@ -881,7 +881,7 @@
 
 - for Markdown tables, `kable()` gained a new argument `padding` to specify the inner padding of table cells using spaces (thanks, @gavril0, #699)
 
-- added a new vignette engine called `rmarkdown`, which uses `rmarkdown::render()` to create a package vignette from an R Markdown document; see http://rmarkdown.rstudio.com for more information about the **rmarkdown** package, and the vignette `knit_print.Rmd` in **knitr** for an example (basically you specify `\VignetteEngine{knitr::rmarkdown}` in your vignette)
+- added a new vignette engine called `rmarkdown`, which uses `rmarkdown::render()` to create a package vignette from an R Markdown document; see https://rmarkdown.rstudio.com for more information about the **rmarkdown** package, and the vignette `knit_print.Rmd` in **knitr** for an example (basically you specify `\VignetteEngine{knitr::rmarkdown}` in your vignette)
 
 - indentation is preserved when using chunk references `<<>>`, i.e., if `<<>>` is indented, the spaces before it will be applied to the code that it refers to (thanks, Terry Therneau)
 
diff --git a/R/pandoc.R b/R/pandoc.R
index 2b06c18d9b..b8e97eed76 100644
--- a/R/pandoc.R
+++ b/R/pandoc.R
@@ -37,7 +37,7 @@
 #' @references Pandoc: \url{https://pandoc.org}; Examples and rules of the
 #'   configurations: \url{https://yihui.org/knitr/demo/pandoc/}
 #'
-#'   Also see R Markdown (v2) at \url{http://rmarkdown.rstudio.com}. The
+#'   Also see R Markdown (v2) at \url{https://rmarkdown.rstudio.com}. The
 #'   \pkg{rmarkdown} package has several convenience functions and templates
 #'   that make it very easy to use Pandoc. The RStudio IDE also has
 #'   comprehensive support for it, so I'd recommend users who are not familiar
diff --git a/R/themes.R b/R/themes.R
index 165dce78b8..ee7875058c 100644
--- a/R/themes.R
+++ b/R/themes.R
@@ -33,7 +33,7 @@ get_theme = function(theme = NULL) {
 #' @note The syntax highlighting here only applies to \file{.Rnw} (LaTeX) and
 #'   \file{.Rhtml} (HTML) documents, and it does not work for other types of
 #'   documents, such as \file{.Rmd} (R Markdown, which has its own syntax
-#'   highlighting themes; see \url{http://rmarkdown.rstudio.com}).
+#'   highlighting themes; see \url{https://rmarkdown.rstudio.com}).
 #' @export
 #' @examples opts_knit$set(out.format='latex'); knit_theme$set('edit-vim')
 #'
diff --git a/inst/examples/knitr-manual.bib b/inst/examples/knitr-manual.bib
index 13a90cdfba..0cac45c6da 100644
--- a/inst/examples/knitr-manual.bib
+++ b/inst/examples/knitr-manual.bib
@@ -16,5 +16,5 @@ @book{xie2013
   year = {2015},
   edition = {2nd},
   note = {ISBN 978-1498716963},
-  url = {http://yihui.org/knitr/}
+  url = {https://yihui.org/knitr/}
 }
diff --git a/inst/examples/knitr-packages.bib b/inst/examples/knitr-packages.bib
index e5957873ca..a434a2e65b 100644
--- a/inst/examples/knitr-packages.bib
+++ b/inst/examples/knitr-packages.bib
@@ -62,7 +62,7 @@ @Manual{R-knitr
   author = {Yihui Xie},
   year = {2016},
   note = {R package version 1.15},
-  url = {http://yihui.org/knitr/},
+  url = {https://yihui.org/knitr/},
 }
 @Manual{R-MASS,
   title = {MASS: Support Functions and Datasets for Venables and Ripley's MASS},
diff --git a/man/knit_theme.Rd b/man/knit_theme.Rd
index b0e1e9ee97..b58b8f76dc 100644
--- a/man/knit_theme.Rd
+++ b/man/knit_theme.Rd
@@ -25,7 +25,7 @@ returned by the \code{get()} method. See examples below.
 The syntax highlighting here only applies to \file{.Rnw} (LaTeX) and
   \file{.Rhtml} (HTML) documents, and it does not work for other types of
   documents, such as \file{.Rmd} (R Markdown, which has its own syntax
-  highlighting themes; see \url{http://rmarkdown.rstudio.com}).
+  highlighting themes; see \url{https://rmarkdown.rstudio.com}).
 }
 \examples{
 opts_knit$set(out.format = "latex")
diff --git a/man/pandoc.Rd b/man/pandoc.Rd
index 887cf28643..79d7f32fee 100644
--- a/man/pandoc.Rd
+++ b/man/pandoc.Rd
@@ -57,7 +57,7 @@ system("pandoc -h")  # see possible output formats
 Pandoc: \url{https://pandoc.org}; Examples and rules of the
   configurations: \url{https://yihui.org/knitr/demo/pandoc/}
 
-  Also see R Markdown (v2) at \url{http://rmarkdown.rstudio.com}. The
+  Also see R Markdown (v2) at \url{https://rmarkdown.rstudio.com}. The
   \pkg{rmarkdown} package has several convenience functions and templates
   that make it very easy to use Pandoc. The RStudio IDE also has
   comprehensive support for it, so I'd recommend users who are not familiar
diff --git a/vignettes/knitr-markdown.Rmd b/vignettes/knitr-markdown.Rmd
index 883f6e9ac2..9f7e286ec1 100644
--- a/vignettes/knitr-markdown.Rmd
+++ b/vignettes/knitr-markdown.Rmd
@@ -8,7 +8,7 @@ library(knitr)
 
 This is an example of Markdown vignettes in R. Before R 3.0.0, only Sweave/PDF vignettes were supported in R. Markdown is gaining popularity over the years due to its simplicity, and R 3.0.0 starts to support package vignettes written in R Markdown.
 
-> Please note this example is for [R Markdown v1](http://rmarkdown.rstudio.com/authoring_migrating_from_v1.html) only. If you use [R Markdown v2](http://rmarkdown.rstudio.com/), you should use the vignette engine `knitr::rmarkdown` instead of `knitr::knitr`.
+> Please note this example is for [R Markdown v1](https://rmarkdown.rstudio.com/authoring_migrating_from_v1.html) only. If you use [R Markdown v2](https://rmarkdown.rstudio.com/), you should use the vignette engine `knitr::rmarkdown` instead of `knitr::knitr`.
 
 ## Package vignettes