diff --git a/lib/qiita/markdown.rb b/lib/qiita/markdown.rb
index 8b1f362..ae84706 100644
--- a/lib/qiita/markdown.rb
+++ b/lib/qiita/markdown.rb
@@ -1,5 +1,5 @@
 require "cgi"
-require "html/pipeline"
+require "html_pipeline"
 require "linguist"
 require "mem"
 require "nokogiri"
diff --git a/lib/qiita/markdown/base_processor.rb b/lib/qiita/markdown/base_processor.rb
index 1d83ced..d6f22cb 100644
--- a/lib/qiita/markdown/base_processor.rb
+++ b/lib/qiita/markdown/base_processor.rb
@@ -33,7 +33,7 @@ def call(input, context = {})
       end
 
       # @note Modify filters if you want.
-      # @return [Array<HTML::Pipeline::Filter>]
+      # @return [Array<HTMLPipelineFilter>]
       def filters
         @filters ||= self.class.default_filters
       end
diff --git a/lib/qiita/markdown/filters/checkbox.rb b/lib/qiita/markdown/filters/checkbox.rb
index c014afc..d3b01f5 100644
--- a/lib/qiita/markdown/filters/checkbox.rb
+++ b/lib/qiita/markdown/filters/checkbox.rb
@@ -7,7 +7,7 @@ module Filters
       # * [ ] Bar
       # * [ ] Baz
       #
-      class Checkbox < HTML::Pipeline::Filter
+      class Checkbox < ::HTMLPipelineFilter
         def call
           doc.search("li").each do |li|
             list = List.new(li)
diff --git a/lib/qiita/markdown/filters/code_block.rb b/lib/qiita/markdown/filters/code_block.rb
index d10eed3..e8444f2 100644
--- a/lib/qiita/markdown/filters/code_block.rb
+++ b/lib/qiita/markdown/filters/code_block.rb
@@ -12,7 +12,7 @@ module Filters
       # 3. Adds detected code data into `result[:codes]`.
       #
       # You can pass language aliases table via context[:language_aliases].
-      class CodeBlock < HTML::Pipeline::Filter
+      class CodeBlock < ::HTMLPipelineFilter
         def call
           result[:codes] ||= []
           doc.search("pre").each do |pre|
diff --git a/lib/qiita/markdown/filters/custom_block.rb b/lib/qiita/markdown/filters/custom_block.rb
index b883aac..63a9675 100644
--- a/lib/qiita/markdown/filters/custom_block.rb
+++ b/lib/qiita/markdown/filters/custom_block.rb
@@ -3,7 +3,7 @@
 module Qiita
   module Markdown
     module Filters
-      class CustomBlock < HTML::Pipeline::Filter
+      class CustomBlock < ::HTMLPipelineFilter
         ALLOWED_TYPES = %w[note].freeze
 
         def call
diff --git a/lib/qiita/markdown/filters/external_link.rb b/lib/qiita/markdown/filters/external_link.rb
index cbeb082..0bfe271 100644
--- a/lib/qiita/markdown/filters/external_link.rb
+++ b/lib/qiita/markdown/filters/external_link.rb
@@ -3,7 +3,7 @@
 module Qiita
   module Markdown
     module Filters
-      class ExternalLink < HTML::Pipeline::Filter
+      class ExternalLink < ::HTMLPipelineFilter
         def call
           doc.search("a").each do |anchor|
             next unless anchor["href"]
diff --git a/lib/qiita/markdown/filters/final_sanitizer.rb b/lib/qiita/markdown/filters/final_sanitizer.rb
index 878508f..56253f9 100644
--- a/lib/qiita/markdown/filters/final_sanitizer.rb
+++ b/lib/qiita/markdown/filters/final_sanitizer.rb
@@ -11,7 +11,7 @@ module Filters
       # generated by other filters.
       #
       # @see Qiita::Markdown::Filters::UserInputSanitizerr
-      class FinalSanitizer < ::HTML::Pipeline::Filter
+      class FinalSanitizer < ::HTMLPipelineFilter
         RULE = {
           attributes: {
             "a" => %w[
diff --git a/lib/qiita/markdown/filters/footnote.rb b/lib/qiita/markdown/filters/footnote.rb
index 351e698..0debbb2 100644
--- a/lib/qiita/markdown/filters/footnote.rb
+++ b/lib/qiita/markdown/filters/footnote.rb
@@ -1,7 +1,7 @@
 module Qiita
   module Markdown
     module Filters
-      class Footnote < HTML::Pipeline::Filter
+      class Footnote < ::HTMLPipelineFilter
         def call
           doc.search("sup > a").each do |a|
             footnote = find_footnote(a)
diff --git a/lib/qiita/markdown/filters/group_mention.rb b/lib/qiita/markdown/filters/group_mention.rb
index 7389d25..e550961 100644
--- a/lib/qiita/markdown/filters/group_mention.rb
+++ b/lib/qiita/markdown/filters/group_mention.rb
@@ -1,7 +1,7 @@
 module Qiita
   module Markdown
     module Filters
-      class GroupMention < HTML::Pipeline::Filter
+      class GroupMention < ::HTMLPipelineFilter
         # @note Override
         def call
           if context[:group_mention_url_generator]
diff --git a/lib/qiita/markdown/filters/heading_anchor.rb b/lib/qiita/markdown/filters/heading_anchor.rb
index 01891aa..64cc96d 100644
--- a/lib/qiita/markdown/filters/heading_anchor.rb
+++ b/lib/qiita/markdown/filters/heading_anchor.rb
@@ -3,7 +3,7 @@
 module Qiita
   module Markdown
     module Filters
-      class HeadingAnchor < ::HTML::Pipeline::Filter
+      class HeadingAnchor < ::HTMLPipelineFilter
         def call
           doc.search("h1, h2, h3, h4, h5, h6").each do |heading|
             heading["id"] = suffixed_id(heading)
diff --git a/lib/qiita/markdown/filters/html_toc.rb b/lib/qiita/markdown/filters/html_toc.rb
index 346f7ba..b366f6c 100644
--- a/lib/qiita/markdown/filters/html_toc.rb
+++ b/lib/qiita/markdown/filters/html_toc.rb
@@ -3,7 +3,7 @@
 module Qiita
   module Markdown
     module Filters
-      class HtmlToc < ::HTML::Pipeline::Filter
+      class HtmlToc < ::HTMLPipelineFilter
         # @return [Nokogiri::HTML::DocumentFragment]
         def call
           headings = doc.search("h1, h2, h3, h4, h5, h6")
diff --git a/lib/qiita/markdown/filters/image_link.rb b/lib/qiita/markdown/filters/image_link.rb
index f8bdba9..3ebe170 100644
--- a/lib/qiita/markdown/filters/image_link.rb
+++ b/lib/qiita/markdown/filters/image_link.rb
@@ -1,7 +1,7 @@
 module Qiita
   module Markdown
     module Filters
-      class ImageLink < HTML::Pipeline::Filter
+      class ImageLink < ::HTMLPipelineFilter
         def call
           doc.search("img").each do |img|
             next if img.ancestors.any? { |ancestor| ancestor.name == "a" }
diff --git a/lib/qiita/markdown/filters/inline_code_color.rb b/lib/qiita/markdown/filters/inline_code_color.rb
index 1505363..2854ac3 100644
--- a/lib/qiita/markdown/filters/inline_code_color.rb
+++ b/lib/qiita/markdown/filters/inline_code_color.rb
@@ -1,7 +1,7 @@
 module Qiita
   module Markdown
     module Filters
-      class InlineCodeColor < HTML::Pipeline::Filter
+      class InlineCodeColor < ::HTMLPipelineFilter
         DEFAULT_CLASS_NAME = "inline-code-color".freeze
 
         REGEXPS = Regexp.union(
diff --git a/lib/qiita/markdown/filters/simplify.rb b/lib/qiita/markdown/filters/simplify.rb
index 1d66b40..4625827 100644
--- a/lib/qiita/markdown/filters/simplify.rb
+++ b/lib/qiita/markdown/filters/simplify.rb
@@ -14,7 +14,7 @@ module Filters
       #   want to clean up only some elements, and they would be run in the
       #   `FinalSanitizer` filter later.
       #   https://github.com/rgrove/sanitize/blob/v3.1.2/lib/sanitize.rb#L77-L100
-      class Simplify < HTML::Pipeline::Filter
+      class Simplify < ::HTMLPipelineFilter
         SIMPLE_ELEMENTS = %w[a b code em i ins q s samp span strike strong sub sup var]
 
         COMPLEX_CONTENT_ELEMENTS = %w[table]
diff --git a/lib/qiita/markdown/filters/syntax_highlight.rb b/lib/qiita/markdown/filters/syntax_highlight.rb
index 5c50a5e..9059251 100644
--- a/lib/qiita/markdown/filters/syntax_highlight.rb
+++ b/lib/qiita/markdown/filters/syntax_highlight.rb
@@ -1,7 +1,7 @@
 module Qiita
   module Markdown
     module Filters
-      class SyntaxHighlight < HTML::Pipeline::Filter
+      class SyntaxHighlight < ::HTMLPipelineFilter
         DEFAULT_LANGUAGE = "text"
         DEFAULT_TIMEOUT = Float::INFINITY
         DEFAULT_OPTION = "html_legacy"
diff --git a/lib/qiita/markdown/filters/toc.rb b/lib/qiita/markdown/filters/toc.rb
index 7d2230d..1ab9d61 100644
--- a/lib/qiita/markdown/filters/toc.rb
+++ b/lib/qiita/markdown/filters/toc.rb
@@ -1,7 +1,7 @@
 module Qiita
   module Markdown
     module Filters
-      class Toc < HTML::Pipeline::Filter
+      class Toc < ::HTMLPipelineFilter
         def call
           doc.css("h1[id], h2[id], h3[id], h4[id], h5[id], h6[id]").each do |node|
             Heading.new(node).decorate
diff --git a/lib/qiita/markdown/filters/truncate.rb b/lib/qiita/markdown/filters/truncate.rb
index 9906c60..7eb425f 100644
--- a/lib/qiita/markdown/filters/truncate.rb
+++ b/lib/qiita/markdown/filters/truncate.rb
@@ -8,7 +8,7 @@ module Filters
       #
       # @example
       #   Truncate.new(doc, truncate: { length: 50, omission: '... (continued)' })
-      class Truncate < HTML::Pipeline::Filter
+      class Truncate < ::HTMLPipelineFilter
         DEFAULT_OPTIONS = {
           length: 100,
           omission: "…".freeze,
diff --git a/lib/qiita/markdown/filters/user_input_sanitizer.rb b/lib/qiita/markdown/filters/user_input_sanitizer.rb
index ca94082..4815a06 100644
--- a/lib/qiita/markdown/filters/user_input_sanitizer.rb
+++ b/lib/qiita/markdown/filters/user_input_sanitizer.rb
@@ -4,7 +4,7 @@ module Qiita
   module Markdown
     module Filters
       # Sanitizes user input if :strict context is given.
-      class UserInputSanitizer < ::HTML::Pipeline::Filter
+      class UserInputSanitizer < ::HTMLPipelineFilter
         RULE = {
           elements: %w[
             a b blockquote br caption code dd del details div dl dt em font h1 h2 h3 h4 h5 h6
diff --git a/qiita-markdown.gemspec b/qiita-markdown.gemspec
index 47e4920..b265aa4 100644
--- a/qiita-markdown.gemspec
+++ b/qiita-markdown.gemspec
@@ -20,7 +20,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency "addressable"
   spec.add_dependency "gemoji"
   spec.add_dependency "github-linguist", "~> 7.0"
-  spec.add_dependency "html-pipeline", "~> 2.0"
+  spec.add_dependency "html-pipeline", ">= 2", "< 4"
   spec.add_dependency "mem"
   spec.add_dependency "qiita_marker", "~> 0.23.9"
   spec.add_dependency "rouge", "~> 4.2"