diff --git a/db/migrate/20240321211120_add_in_reply_to_to_posts.rb b/db/migrate/20240321211120_add_in_reply_to_to_posts.rb
new file mode 100644
index 0000000..a8ddcdf
--- /dev/null
+++ b/db/migrate/20240321211120_add_in_reply_to_to_posts.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+ROM::SQL.migration do
+  change do
+    alter_table :posts do
+      add_column :in_reply_to, :text
+    end
+  end
+end
diff --git a/lib/adamantium/jobs/send_web_mentions.rb b/lib/adamantium/jobs/send_web_mentions.rb
index 1ab7a38..cbbb054 100644
--- a/lib/adamantium/jobs/send_web_mentions.rb
+++ b/lib/adamantium/jobs/send_web_mentions.rb
@@ -4,7 +4,7 @@ require "que"
 module Adamantium
   module Jobs
     class SendWebMentions < Que::Job
-      def run(post_content:, post_url:)
+      def run(post_content:, post_url:, in_reply_to:)
         link_finder = Admin::Container["post_utilities.link_finder"]
         settings = Admin::Container["settings"]
 
@@ -17,6 +17,15 @@ module Adamantium
             target: target
           })
         end
+
+        links = link_finder.call(in_reply_to)
+        links.each do |target|
+          HTTParty.post(settings.webmention_url, {
+            token: settings.webmention_token,
+            source: source,
+            target: target
+          })
+        end
       end
     end
   end
diff --git a/lib/adamantium/link_finder.rb b/lib/adamantium/link_finder.rb
index 3203375..7b4d496 100644
--- a/lib/adamantium/link_finder.rb
+++ b/lib/adamantium/link_finder.rb
@@ -9,6 +9,7 @@ module Adamantium
       youtube.com
       bsky.app
       bsky.social
+      localhost
       github.com].freeze
 
     def call(content)
diff --git a/slices/main/repos/post_repo.rb b/slices/main/repos/post_repo.rb
index 72eab04..c59fc74 100644
--- a/slices/main/repos/post_repo.rb
+++ b/slices/main/repos/post_repo.rb
@@ -192,6 +192,17 @@ module Main
           .one!
       end
 
+      def fetch(slug)
+        posts
+          .published
+          .combine(:tags, :trips, :webmentions)
+          .node(:webmentions) { |webmention|
+            webmention.published.where(type: "reply")
+          }
+          .where(slug: slug)
+          .one
+      end
+
       def find!(id)
         posts
           .by_pk(id)
diff --git a/slices/main/templates/posts/show.html.slim b/slices/main/templates/posts/show.html.slim
index f2ecbc1..fa55824 100644
--- a/slices/main/templates/posts/show.html.slim
+++ b/slices/main/templates/posts/show.html.slim
@@ -17,6 +17,13 @@ article class="h-entry"
     h1 class="p-name mb-2"
       a class="u-url" href=post.permalink
         = post.display_title
+    - if post.in_reply_to
+      div class=""
+        em = "In reply to: "
+        - if reply_in_context
+          a class="no-underline bg-pink-50 hover:bg-pink-100 dark:bg-pink-600 hover:dark:bg-pink-900 p-1 rounded" href=post.in_reply_to #{reply_in_context.display_title}
+        - else
+          a class="no-underline bg-pink-50 hover:bg-pink-100 dark:bg-pink-600 hover:dark:bg-pink-900 p-1 rounded" href=post.in_reply_to #{post.in_reply_to}
     nav class="space-x-1 text-sm md:text-sm md:block dark:text-gray-600"
       - if post.location || post.photos? || post.videos?
         span See more:
diff --git a/slices/main/views/posts/show.rb b/slices/main/views/posts/show.rb
index f9122ce..fade162 100644
--- a/slices/main/views/posts/show.rb
+++ b/slices/main/views/posts/show.rb
@@ -4,7 +4,7 @@ module Main
   module Views
     module Posts
       class Show < Main::View
-        include Deps["repos.post_repo", "repos.movie_repo"]
+        include Deps["repos.post_repo", "repos.movie_repo", "settings"]
 
         expose :post do |slug:|
           Decorators::Posts::Decorator.new(post_repo.fetch!(slug))
@@ -35,6 +35,13 @@ module Main
         expose :trip do |post|
           post.trips.first
         end
+
+        expose :reply_in_context do |post|
+          if post.in_reply_to&.match settings.micropub_site_url
+            slug = post.in_reply_to.split("/").last
+            Decorators::Posts::Decorator.new(post_repo.fetch(slug))
+          end
+        end
       end
     end
   end
diff --git a/slices/micropub/commands/posts/create_post.rb b/slices/micropub/commands/posts/create_post.rb
index 915e145..0211696 100644
--- a/slices/micropub/commands/posts/create_post.rb
+++ b/slices/micropub/commands/posts/create_post.rb
@@ -24,7 +24,7 @@ module Micropub
 
           decorated_post = Decorators::Posts::Decorator.new(created_post)
 
-          send_webmentions.call(post_content: created_post.content, post_url: decorated_post.permalink)
+          send_webmentions.call(post_content: created_post.content, post_url: decorated_post.permalink, in_reply_to: created_post.in_reply_to)
 
           Success(created_post)
         end
diff --git a/slices/micropub/commands/posts/send_webmentions.rb b/slices/micropub/commands/posts/send_webmentions.rb
index 2ab7579..bc6b3ba 100644
--- a/slices/micropub/commands/posts/send_webmentions.rb
+++ b/slices/micropub/commands/posts/send_webmentions.rb
@@ -7,10 +7,10 @@ module Micropub
       class SendWebmentions
         include Deps["settings", "post_utilities.link_finder"]
 
-        def call(post_content:, post_url:)
+        def call(post_content:, post_url:, in_reply_to:)
           Que.connection = Adamantium::Container["persistence.db"]
 
-          Adamantium::Jobs::SendWebMentions.enqueue(post_content: post_content, post_url: post_url)
+          Adamantium::Jobs::SendWebMentions.enqueue(post_content: post_content, post_url: post_url, in_reply_to: in_reply_to)
         end
       end
     end
diff --git a/slices/micropub/entities/post_request.rb b/slices/micropub/entities/post_request.rb
index 3cc1d4d..6c84117 100644
--- a/slices/micropub/entities/post_request.rb
+++ b/slices/micropub/entities/post_request.rb
@@ -10,6 +10,7 @@ module Micropub
       attribute :published_at, Types::Nominal::DateTime.optional
       attribute :post_type, Types::Coercible::String
       attribute :syndicate_to, Types::Array.of(Types::Coercible::String)
+      attribute :in_reply_to, Types::Coercible::String
       attribute :photos, Types::Array.of(Types::Hash)
       attribute :location, Types::Coercible::String.optional
     end
diff --git a/slices/micropub/request_parser.rb b/slices/micropub/request_parser.rb
index 1e98548..ff27228 100644
--- a/slices/micropub/request_parser.rb
+++ b/slices/micropub/request_parser.rb
@@ -97,6 +97,7 @@ module Micropub
           content: content,
           slug: params[:slug] || params[:"mp-slug"],
           syndicate_to: Array(params[:properties][:"mp-syndicate-to"]) || [],
+          in_reply_to: params[:properties][:"in-reply-to"] || nil,
           photos: photos,
           location: params[:properties][:location]
         })
@@ -119,6 +120,7 @@ module Micropub
 
         new_params.merge({
           syndicate_to: Array(params[:"mp-syndicate-to"]) || [],
+          in_reply_to: params[:"in-reply-to"],
           name: params[:name],
           slug: params[:slug] || params[:"mp-slug"],
           published_at: (params[:"post-status"] == "draft") ? nil : publish_time,
diff --git a/slices/micropub/validation/posts/post_contract.rb b/slices/micropub/validation/posts/post_contract.rb
index f35afad..7cdcb0f 100644
--- a/slices/micropub/validation/posts/post_contract.rb
+++ b/slices/micropub/validation/posts/post_contract.rb
@@ -12,6 +12,7 @@ module Micropub
           required(:syndicate_to).array(:string)
           required(:photos).array(:hash)
           required(:location).maybe(:string)
+          required(:in_reply_to).maybe(:string)
         end
       end
     end
diff --git a/spec/syndication/unit/mastodon_spec.rb b/spec/syndication/unit/mastodon_spec.rb
index d2b10af..e882547 100644
--- a/spec/syndication/unit/mastodon_spec.rb
+++ b/spec/syndication/unit/mastodon_spec.rb
@@ -20,7 +20,8 @@ RSpec.describe Adamantium::Syndication::Mastodon do
         post_type: "post",
         syndicate_to: [],
         photos: [],
-        location: nil
+        location: nil,
+        in_reply_to: nil
       )
     }