diff --git a/README.md b/README.md
index 3a2cf2b..811b9f1 100644
--- a/README.md
+++ b/README.md
@@ -48,6 +48,7 @@ linters:
 - [GitHub::Accessibility::NoPositiveTabIndex](./docs/rules/accessibility/no-positive-tab-index.md)
 - [GitHub::Accessibility::NoRedundantImageAlt](./docs/rules/accessibility/no-redundant-image-alt.md)
 - [GitHub::Accessibility::NoTitleAttributeCounter](./docs/rules/accessibility/no-title-attribute-counter.md)
+- [GitHub::Accessibility::DetailsHasSummary](./docs/rules/accessibility/details-has-summary.md)
 
 ## Testing
 
diff --git a/docs/rules/accessibility/details-has-summary.md b/docs/rules/accessibility/details-has-summary.md
new file mode 100644
index 0000000..bb671b0
--- /dev/null
+++ b/docs/rules/accessibility/details-has-summary.md
@@ -0,0 +1,35 @@
+# Details has summary
+
+## Rule Details
+`<details>` should have a `<summary>` element hinting to the user what they'll be expanding by interfacing with the element. `<summary>` elements are helpful for screen reader users navigating the website. They are also a good UI pattern since a user agent adds their own `<summary>` if a developer omitted it with no context on what UI the details element will expand.
+
+### 👎 Examples of **incorrect** code for this rule:
+
+```erb
+<details>
+  I don't have a summary tag!
+</details>
+```
+
+```erb
+<details>
+  <div><summary>Expand me!</summary></div>
+  I have a invalid summary tag! The summary tag needs to be a direct child of the details tag.
+</details>
+```
+
+### 👍 Examples of **correct** code for this rule:
+
+```erb
+<details>
+  <summary>Expand me!</summary>
+  I do have a summary tag!
+</details>
+````
+
+```erb
+<details>
+  I do have a summary tag!
+  <summary>Expand me!</summary>
+</details>
+````
diff --git a/lib/erblint-github/linters/github/accessibility/details_has_summary.rb b/lib/erblint-github/linters/github/accessibility/details_has_summary.rb
new file mode 100644
index 0000000..03a6ae7
--- /dev/null
+++ b/lib/erblint-github/linters/github/accessibility/details_has_summary.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require_relative "../../custom_helpers"
+require_relative "../../tag_tree_helpers"
+
+module ERBLint
+  module Linters
+    module GitHub
+      module Accessibility
+        class DetailsHasSummary < Linter
+          include ERBLint::Linters::CustomHelpers
+          include ERBLint::Linters::TagTreeHelpers
+          include LinterRegistry
+
+          MESSAGE = "<details> elements need to have explicit <summary> element"
+
+          def run(processed_source)
+            has_summary = false
+
+            (tags, tag_tree) = build_tag_tree(processed_source)
+
+            tags.each do |tag|
+              next if tag.name != "details" || tag.closing?
+
+              details = tag_tree[tag]
+
+              details[:children].each do |child|
+                if child[:tag].name == "summary"
+                  has_summary = true
+                  break
+                end
+
+                erb_nodes = extract_erb_nodes(child[:tag].node)
+
+                next if erb_nodes.blank?
+
+                code = ""
+
+                erb_nodes.each do |erb_node|
+                  _, _, code_node = *erb_node
+                  code += code_node.children.first
+                end
+
+                ast = erb_ast(code)
+
+                ast = ast.children.first if ast.type == :block
+                next unless ast.method_name == :content_tag
+
+                if ast.arguments.first.value.to_s == "summary"
+                  has_summary = true
+                  break
+                end
+              end
+
+              generate_offense(self.class, processed_source, details[:tag]) unless has_summary
+
+              has_summary = false
+            end
+
+            rule_disabled?(processed_source)
+          end
+
+          private
+
+          def extract_erb_nodes(node)
+            return node if node.type == :erb
+            return nil unless node.type == :text
+
+            node.children.select { |x| x.try(:type) == :erb }
+          end
+
+          def erb_ast(code)
+            RuboCop::AST::ProcessedSource.new(code, RUBY_VERSION.to_f).ast
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/erblint-github/linters/tag_tree_helpers.rb b/lib/erblint-github/linters/tag_tree_helpers.rb
new file mode 100644
index 0000000..5889f1f
--- /dev/null
+++ b/lib/erblint-github/linters/tag_tree_helpers.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+module ERBLint
+  module Linters
+    # Helpers used by linters to organize HTML tags into abstract syntax trees.
+    module TagTreeHelpers
+      # from https://github.com/Shopify/erb-lint/blob/6179ee2d9d681a6ec4dd02351a1e30eefa748d3d/lib/erb_lint/linters/self_closing_tag.rb
+      SELF_CLOSING_TAGS = %w[
+        area base br col command embed hr input keygen
+        link menuitem meta param source track wbr img
+      ].freeze
+
+      # This assumes that the AST provided represents valid HTML, where each tag has a corresponding closing tag.
+      # From the tags, we build a structured tree which represents the tag hierarchy.
+      # With this, we are able to know where the tags start and end.
+      def build_tag_tree(processed_source)
+        nodes = processed_source.ast.children
+        tag_tree = {}
+        tags = []
+        current_opened_tag = nil
+
+        nodes.each do |node|
+          tag = BetterHtml::Tree::Tag.from_node(node)
+
+          if node.type == :tag
+            # get the tag from previously calculated list so the references are the same
+            tags << tag
+
+            if tag.closing?
+              if current_opened_tag && tag.name == current_opened_tag.name
+                tag_tree[current_opened_tag][:closing] = tag
+                current_opened_tag = tag_tree[current_opened_tag][:parent]
+              end
+
+              next
+            end
+
+            self_closing = self_closing?(tag)
+
+            tag_tree[tag] = {
+              tag: tag,
+              closing: self_closing ? tag : nil,
+              parent: current_opened_tag,
+              children: []
+            }
+
+            tag_tree[current_opened_tag][:children] << tag_tree[tag] if current_opened_tag
+            current_opened_tag = tag unless self_closing
+          elsif current_opened_tag
+            tag_tree[current_opened_tag][:children] << {
+              tag: tag,
+              closing: tag,
+              parent: current_opened_tag,
+              children: []
+            }
+          end
+        end
+
+        [tags, tag_tree]
+      end
+
+      def self_closing?(tag)
+        tag.self_closing? || SELF_CLOSING_TAGS.include?(tag.name)
+      end
+    end
+  end
+end
diff --git a/test/linters/accessibility/details_has_summary_test.rb b/test/linters/accessibility/details_has_summary_test.rb
new file mode 100644
index 0000000..54324c1
--- /dev/null
+++ b/test/linters/accessibility/details_has_summary_test.rb
@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class DetailsHasSummary < LinterTestCase
+  def linter_class
+    ERBLint::Linters::GitHub::Accessibility::DetailsHasSummary
+  end
+
+  def test_warns_if_details_doesnt_have_a_summary
+    @file = "<details>I don't have a summary element</details>"
+    @linter.run(processed_source)
+
+    assert_equal 1, @linter.offenses.count
+  end
+
+  def test_does_not_warn_if_details_has_a_summary_in_a_weird_place
+    @file = "<details><p>Surprise text!</p><summary>Expand me!</summary></details>"
+    @linter.run(processed_source)
+
+    assert_empty @linter.offenses
+  end
+
+  def test_does_not_warn_if_details_has_a_summary
+    @file = "<details><summary>Expand me!</summary><button>Surprise button!</button></details>"
+    @linter.run(processed_source)
+
+    assert_empty @linter.offenses
+  end
+
+  def test_does_warns_if_details_has_a_summary_as_an_inner_child
+    @file = "<details><p><summary>Expand me!</summary></p><button>Surprise button!</button></details>"
+    @linter.run(processed_source)
+
+    assert_equal 1, @linter.offenses.count
+  end
+
+  def test_doesnt_warns_if_details_has_a_summary_content_tag
+    @file = <<~ERB
+      <details>
+        <%= content_tag(:summary) { "Expand me!" } %>
+        <p>Surprise text!</p>
+      </details>
+    ERB
+    @linter.run(processed_source)
+
+    assert_empty @linter.offenses
+  end
+
+  def test_doesnt_warns_if_details_has_a_summary_content_tag_with_do_block
+    @file = <<~ERB
+      <details>
+        <%= content_tag(:summary) do %>
+          Expand me!
+        <% end %>
+        <p>Surprise text!</p>
+      </details>
+    ERB
+    @linter.run(processed_source)
+
+    assert_empty @linter.offenses
+  end
+
+  def test_warns_if_details_has_a_non_summary_content_tag
+    @file = <<~ERB
+      <details>
+        <%= content_tag(:div) { "Expand me!" } %>
+        <p>Surprise text!</p>
+      </details>
+    ERB
+    @linter.run(processed_source)
+
+    assert_equal 1, @linter.offenses.count
+  end
+end
diff --git a/test/linters/tag_tree_helpers_test.rb b/test/linters/tag_tree_helpers_test.rb
new file mode 100644
index 0000000..f4fdf82
--- /dev/null
+++ b/test/linters/tag_tree_helpers_test.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require_relative "../../lib/erblint-github/linters/tag_tree_helpers"
+
+class TagTreeHelpers < Minitest::Test
+  include ERBLint::Linters::TagTreeHelpers
+
+  def test_build_tree
+    file = %{
+      <html>
+        <head>
+          <title>Hello</title>
+        </head>
+        <body>
+          <h1>Hello</h1>
+          Welcome to my page!
+        </body>
+      </html>
+    }
+    processed_source = ERBLint::ProcessedSource.new("file.rb", file)
+    tags, tree = build_tag_tree(processed_source)
+
+    html_tag = tags.first
+
+    assert_equal "html", html_tag.name
+
+    children = tree[html_tag][:children].filter do |child|
+      child[:tag].name
+    end
+
+    assert_equal 2, children.length
+    assert_equal "head", children[0][:tag].name
+
+    body_tag = children[1][:tag]
+    assert_equal "body", body_tag.name
+
+    h1_tag = tree[body_tag][:children].filter{ |child| child[:tag].name }.first[:tag]
+    assert_equal "h1", h1_tag.name
+  end
+end