diff --git a/NEWS.md b/NEWS.md
index ccd5d57d7..4e611c79b 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -4,7 +4,7 @@
 
 # CHANGES IN bookdown VERSION 0.38
 
-- Fixed a bug that `gitbook()` may geneate an empty search index on certain platforms (thanks, @UlvHare, #1454).
+- Fixed a bug that `gitbook()` may generate an empty search index on certain platforms (thanks, @UlvHare, #1454).
 
 # CHANGES IN bookdown VERSION 0.37
 
diff --git a/R/html.R b/R/html.R
index e5298ec4a..3de2b9c2a 100644
--- a/R/html.R
+++ b/R/html.R
@@ -704,7 +704,7 @@ parse_fig_labels = function(content, global = FALSE) {
     # there could be multiple labels on the same line, but their types must be
     # the same (https://github.com/rstudio/bookdown/issues/538)
     if (length(unique(type)) != 1) stop(
-      'There are mutiple types of labels on one line: ', paste(labs, collapse = ', ')
+      'There are multiple types of labels on one line: ', paste(labs, collapse = ', ')
     )
     type = type[1]
     num = arry[lab]
diff --git a/inst/examples/03-formats.Rmd b/inst/examples/03-formats.Rmd
index b15e31232..ac72d161f 100644
--- a/inst/examples/03-formats.Rmd
+++ b/inst/examples/03-formats.Rmd
@@ -317,7 +317,7 @@ description: |
 
 The `bs4_book()` format builds upon the Bootstrap CSS framework ([version 4](https://getbootstrap.com/docs/4.0/)), an open source library of reusable chunks of HTML, CSS, and JavaScript code. The Bootstrap framework allows for easy customization of colors and fonts via the **bslib** R package.
 
-You can use the `theme` option to add a `primary` color in [hexidecimal format,](https://en.wikipedia.org/wiki/Web_colors) which will change the color of all links in your book and the background color of the footer.
+You can use the `theme` option to add a `primary` color in [hexadecimal format,](https://en.wikipedia.org/wiki/Web_colors) which will change the color of all links in your book and the background color of the footer.
 
 ```yaml
 bookdown::bs4_book:
diff --git a/inst/examples/krantz.cls b/inst/examples/krantz.cls
index d2456699d..ebe8bd574 100755
--- a/inst/examples/krantz.cls
+++ b/inst/examples/krantz.cls
@@ -237,7 +237,7 @@
 \newdimen\tempa
 \newdimen\tempdimen
 %
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  Parameter Initializaton %%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  Parameter Initialization %%%%%%%%%%%%%%%%%%%%%%%%%%
 %
 \newdimen\htrim
 \newdimen\vtrimtop
@@ -1145,7 +1145,7 @@
     \else
       \@cons{\@authors}{, \last@author}\fi\fi
   \stepcounter{numauthors}%
-%%%%%%% commented and deleted below the second part to aviod inaccessible error % shashi % September-2008
+%%%%%%% commented and deleted below the second part to avoid inaccessible error % shashi % September-2008
 %%  \gdef\last@author{#1 {\rm\fontsize{9\p@}{11\p@}\selectfont #2}}
 \gdef\last@author{#1}
 }
diff --git a/inst/resources/gitbook/css/plugin-highlight.css b/inst/resources/gitbook/css/plugin-highlight.css
index 2aabd3deb..02c018910 100644
--- a/inst/resources/gitbook/css/plugin-highlight.css
+++ b/inst/resources/gitbook/css/plugin-highlight.css
@@ -133,7 +133,7 @@
 .book.color-theme-1 .book-body .page-wrapper .page-inner section.normal code {
   /*
 
-Orginal Style from ethanschoonover.com/solarized (c) Jeremy Hull <sourdrums@gmail.com>
+Original Style from ethanschoonover.com/solarized (c) Jeremy Hull <sourdrums@gmail.com>
 
 */
   /* Solarized Green */
diff --git a/inst/resources/gitbook/js/app.js b/inst/resources/gitbook/js/app.js
index dc70f58ad..830ea3f93 100644
--- a/inst/resources/gitbook/js/app.js
+++ b/inst/resources/gitbook/js/app.js
@@ -439,7 +439,7 @@
    * Used by `_.sortByOrder` to compare multiple properties of a value to another
    * and stable sort them.
    *
-   * If `orders` is unspecified, all valuess are sorted in ascending order. Otherwise,
+   * If `orders` is unspecified, all values are sorted in ascending order. Otherwise,
    * a value is sorted in ascending order if its corresponding order is "asc", and
    * descending if "desc".
    *
@@ -923,7 +923,7 @@
      * @private
      * @param {*} value The value to wrap.
      * @param {boolean} [chainAll] Enable chaining for all wrapper methods.
-     * @param {Array} [actions=[]] Actions to peform to resolve the unwrapped value.
+     * @param {Array} [actions=[]] Actions to perform to resolve the unwrapped value.
      */
     function LodashWrapper(value, chainAll, actions) {
       this.__wrapped__ = value;
@@ -2761,7 +2761,7 @@
      *
      * @private
      * @param {*} value The unwrapped value.
-     * @param {Array} actions Actions to peform to resolve the unwrapped value.
+     * @param {Array} actions Actions to perform to resolve the unwrapped value.
      * @returns {*} Returns the resolved value.
      */
     function baseWrapperValue(value, actions) {
@@ -5571,7 +5571,7 @@
     /**
      * Creates a duplicate-free version of an array, using
      * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
-     * for equality comparisons, in which only the first occurence of each element
+     * for equality comparisons, in which only the first occurrence of each element
      * is kept. Providing `true` for `isSorted` performs a faster search algorithm
      * for sorted arrays. If an iteratee function is provided it is invoked for
      * each element in the array to generate the criterion by which uniqueness
@@ -12448,7 +12448,7 @@
 
     /**
      * this is a mapping of keys that require shift on a US keypad
-     * back to the non shift equivelents
+     * back to the non shift equivalents
      *
      * this is so you can use keyup events with these keys
      *
@@ -12504,7 +12504,7 @@
 
     /**
      * loop through the f keys, f1 to f19 and add them to the map
-     * programatically
+     * programmatically
      */
     for (var i = 1; i < 20; ++i) {
         _MAP[111 + i] = 'f' + i;
@@ -12634,7 +12634,7 @@
     }
 
     /**
-     * stops propogation for this event
+     * stops propagation for this event
      *
      * @param {Event} e
      * @returns void
@@ -12952,7 +12952,7 @@
          * actually calls the callback function
          *
          * if your callback function returns false this will use the jquery
-         * convention - prevent default and stop propogation on the event
+         * convention - prevent default and stop propagation on the event
          *
          * @param {Function} callback
          * @param {Event} e
@@ -13669,7 +13669,7 @@ process.nextTick = function (fun) {
     }
 };
 
-// v8 likes predictible objects
+// v8 likes predictable objects
 function Item(fun, array) {
     this.fun = fun;
     this.array = array;
@@ -14671,7 +14671,7 @@ Url.prototype.parse = function(url, parseQueryString, slashesDenoteHost) {
     if (!ipv6Hostname) {
       // IDNA Support: Returns a puny coded representation of "domain".
       // It only converts the part of the domain name that
-      // has non ASCII characters. I.e. it dosent matter if
+      // has non ASCII characters. I.e. it doesn't matter if
       // you call it with a domain that already is in ASCII.
       var domainArray = this.hostname.split('.');
       var newOut = [];
@@ -14981,8 +14981,8 @@ Url.prototype.resolveObject = function(relative) {
     // Put this after the other two cases because it simplifies the booleans
     if (psychotic) {
       result.hostname = result.host = srcPath.shift();
-      //occationaly the auth can get stuck only in host
-      //this especialy happens in cases like
+      //occasionally the auth can get stuck only in host
+      //this especially happens in cases like
       //url.resolveObject('mailto:local1@domain1', 'local2@domain2')
       var authInHost = result.host && result.host.indexOf('@') > 0 ?
                        result.host.split('@') : false;
@@ -15063,8 +15063,8 @@ Url.prototype.resolveObject = function(relative) {
   if (psychotic) {
     result.hostname = result.host = isAbsolute ? '' :
                                     srcPath.length ? srcPath.shift() : '';
-    //occationaly the auth can get stuck only in host
-    //this especialy happens in cases like
+    //occasionally the auth can get stuck only in host
+    //this especially happens in cases like
     //url.resolveObject('mailto:local1@domain1', 'local2@domain2')
     var authInHost = result.host && result.host.indexOf('@') > 0 ?
                      result.host.split('@') : false;
@@ -15444,7 +15444,7 @@ var platform = require('./platform');
 var state = require('./state');
 
 
-// Toggle sidebar with or withour animation
+// Toggle sidebar with or without animation
 function toggleSidebar(_state, animation) {
     if (state != null && isOpen() == _state) return;
     if (animation == null) animation = true;
diff --git a/inst/rmarkdown/lua/custom-environment.lua b/inst/rmarkdown/lua/custom-environment.lua
index 57b01da66..c6081385f 100644
--- a/inst/rmarkdown/lua/custom-environment.lua
+++ b/inst/rmarkdown/lua/custom-environment.lua
@@ -148,7 +148,7 @@ Div = function (div)
             table.insert(div.content[#div.content].content, pandoc.RawInline('tex', '\n' .. endEnv))
         else
             if (div.content[1].t ~= "Para") then
-            -- required trick to get correct alignement
+            -- required trick to get correct alignment
               beginEnv = beginEnv.."\\leavevmode"
             end
             table.insert(div.content, 1, pandoc.RawBlock('tex', beginEnv))
diff --git a/inst/templates/default.html b/inst/templates/default.html
index f92306961..5be47e799 100644
--- a/inst/templates/default.html
+++ b/inst/templates/default.html
@@ -133,7 +133,7 @@
   height: auto;
 }
 /* show arrow before summary tag as in bootstrap
-TODO: remove if boostrap in updated in html_document (rmarkdown#1485) */
+TODO: remove if bootstrap in updated in html_document (rmarkdown#1485) */
 details > summary {
   display: list-item;
   cursor: pointer;
diff --git a/tests/testit/test-html.R b/tests/testit/test-html.R
index 6fa4178de..543765a74 100644
--- a/tests/testit/test-html.R
+++ b/tests/testit/test-html.R
@@ -13,7 +13,7 @@ assert("parse figure reference correctly", {
   (!grepl("(#tab:foo)", res$content, fixed = TRUE))
 })
 
-assert("biblio references section is correcly found", {
+assert("biblio references section is correctly found", {
   # with a csl like https://www.zotero.org/styles/nature
   # reference div have more attributes
   html = c('<div id="references" class="section level1 unnumbered">',
diff --git a/tests/testit/test-utils.R b/tests/testit/test-utils.R
index e560032dd..de32ba206 100644
--- a/tests/testit/test-utils.R
+++ b/tests/testit/test-utils.R
@@ -52,12 +52,12 @@ assert('prepend_chapter_title() adds the chapter title to the page title', {
       '<title>chapter one | asdf qwer</title><meta property="og:title" content="chapter one | asdf qwer" />')
 })
 
-assert('source_files() handles several configurations correcly', {
+assert('source_files() handles several configurations correctly', {
   get_files = function(files = NULL, dirs = NULL, ...) {
     source_files(config = list(rmd_files = files, rmd_subdir = dirs), ...)
   }
 
-  # create dummy projet
+  # create dummy project
   dir.create(project <- tempfile())
   old = setwd(project)
   files = c(