diff --git a/Gemfile b/Gemfile
index fcd1f10..2adaed8 100644
--- a/Gemfile
+++ b/Gemfile
@@ -40,6 +40,7 @@ group :test do
   gem "minitest-rails"
   gem "minitest-spec-rails"
   gem "mocha"
+  gem "rails-controller-testing"
   gem "selenium-webdriver"
   gem "shoulda-context"
   gem "shoulda-matchers"
diff --git a/Gemfile.lock b/Gemfile.lock
index e19305b..75b53e9 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -275,6 +275,10 @@ GEM
     rackup (2.1.0)
       rack (>= 3)
       webrick (~> 1.8)
+    rails-controller-testing (1.0.5)
+      actionpack (>= 5.0.1.rc1)
+      actionview (>= 5.0.1.rc1)
+      activesupport (>= 5.0.1.rc1)
     rails-dom-testing (2.2.0)
       activesupport (>= 5.0.0)
       minitest
@@ -419,6 +423,7 @@ DEPENDENCIES
   pry-rails
   puma (>= 5.0)
   rails!
+  rails-controller-testing
   rbui!
   rubocop-rails-omakase
   selenium-webdriver
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 3b5efbc..41c3366 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -1,5 +1,6 @@
 class ApplicationController < ActionController::Base
   include Authentication
+  include Organizationable
   # Only allow modern browsers supporting webp images, web push, badges, import maps, CSS nesting, and CSS :has.
   # TODO: Turn on after styling is complete.
   # allow_browser versions: :modern
diff --git a/app/controllers/concerns/organizationable.rb b/app/controllers/concerns/organizationable.rb
new file mode 100644
index 0000000..593ea27
--- /dev/null
+++ b/app/controllers/concerns/organizationable.rb
@@ -0,0 +1,21 @@
+module Organizationable
+  extend ActiveSupport::Concern
+
+  included do
+    before_action :assign_organization
+  end
+
+  def current_organization
+    Current.organization || Current.user.base_organization
+  end
+
+  def assign_organization
+    return unless Current.user
+
+    Current.organization = find_organization_by_cookie
+  end
+
+  def find_organization_by_cookie
+    Organization.find_by(id: cookies.signed[:organization_id]) || Current.user.base_organization
+  end
+end
diff --git a/app/controllers/posts_controller.rb b/app/controllers/posts_controller.rb
index ddc7416..7282aa3 100644
--- a/app/controllers/posts_controller.rb
+++ b/app/controllers/posts_controller.rb
@@ -4,7 +4,7 @@ class PostsController < ApplicationController
 
   # GET /posts
   def index
-    @posts = Post.all
+    @posts = current_organization.posts.order(created_at: :desc)
   end
 
   def show
@@ -47,7 +47,12 @@ def set_post
     end
 
     def post_params
-      params.expect(post: [ :title, :message, :user_id ]).merge(user_id: current_user.id)
+      params.expect(
+        post: [ :title, :message, :user_id ]
+      ).merge(
+        user_id: current_user.id,
+        organization_id: current_organization.id
+      )
     end
 
     def authorize_user!
diff --git a/app/controllers/registrations_controller.rb b/app/controllers/registrations_controller.rb
index 8af29e1..b24fbb5 100644
--- a/app/controllers/registrations_controller.rb
+++ b/app/controllers/registrations_controller.rb
@@ -10,7 +10,7 @@ def create
     User.transaction do
       @user = User.new(user_params)
       if @user.save
-        create_organization_for(@user)
+        @user.create_base_organization!
         start_new_session_for(@user)
         redirect_to root_path, notice: "Welcome to PostIt! Start adding projects and tasks."
       else
@@ -32,11 +32,4 @@ def user_params
         ]
       )
     end
-
-    def create_organization_for(user)
-      Organization.transaction do
-        organization = Organization.create!(name: user.name)
-        user.memberships.create!(organization: organization, role: :owner)
-      end
-    end
 end
diff --git a/app/models/current.rb b/app/models/current.rb
index 2bef56d..18ecc59 100644
--- a/app/models/current.rb
+++ b/app/models/current.rb
@@ -1,4 +1,4 @@
 class Current < ActiveSupport::CurrentAttributes
-  attribute :session
+  attribute :session, :organization
   delegate :user, to: :session, allow_nil: true
 end
diff --git a/app/models/organization.rb b/app/models/organization.rb
index 0cf65d1..5ec8fbc 100644
--- a/app/models/organization.rb
+++ b/app/models/organization.rb
@@ -11,4 +11,5 @@ class Organization < ApplicationRecord
 
   has_many :memberships, dependent: :destroy
   has_many :users, through: :memberships
+  has_many :posts, dependent: :destroy
 end
diff --git a/app/models/post.rb b/app/models/post.rb
index 4b3789b..d0788c9 100644
--- a/app/models/post.rb
+++ b/app/models/post.rb
@@ -3,6 +3,7 @@ class Post < ApplicationRecord
   # Associations
   #-----------------------------------------------------------------------------
   belongs_to :user
+  belongs_to :organization
   has_rich_text :message
 
   #-----------------------------------------------------------------------------
diff --git a/app/models/user.rb b/app/models/user.rb
index c95f7ec..0ba025e 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -27,4 +27,18 @@ class User < ApplicationRecord
   #-----------------------------------------------------------------------------
 
   normalizes :email_address, with: ->(e) { e.strip.downcase }
+
+  #-----------------------------------------------------------------------------
+  # Instance Methods
+  #-----------------------------------------------------------------------------
+
+  def base_organization
+    organizations.joins(:memberships).merge(Membership.owner).first || create_base_organization!
+  end
+
+  def create_base_organization!
+    organization = Organization.create!(name: name)
+    memberships.create!(organization: organization, role: :owner)
+    organization
+  end
 end
diff --git a/app/views/posts/show.html.erb b/app/views/posts/show.html.erb
index 9aa99cb..aa4923b 100644
--- a/app/views/posts/show.html.erb
+++ b/app/views/posts/show.html.erb
@@ -1,28 +1,17 @@
 <div class="mx-auto md:w-2/3 w-full flex">
   <div class="mx-auto w-full">
-    <% if notice.present? %>
-      <p class="py-2 px-3 bg-green-50 mb-5 text-green-500 font-medium rounded-lg inline-block" id="notice"><%= notice %></p>
-    <% end %>
-
     <%= render @post %>
 
     <%= render RBUI::Link.new(href: edit_post_path(@post), variant: :outline, class: "me-3") { "Edit" } %>
-    <%#= render RBUI::Link.new(
-      href: post_path(@post),
-      variant: :destructive,
-      data: { turbo_method: :delete, turbo_confirm: "Are you sure you want to delete this post?" },
-      class: "ms-3") {
-        "Delete"
-      } %>
 
-      <%= render Components::ConfirmDialog.new(
-        variant: :destructive,
-        href: post_path(@post),
-        title: "Are you sure?",
-        description: "This action cannot be undone. This will permanently delete your post.",
-        action_text: "Delete post",
-        cancel_text: "Cancel",
-        data: { turbo_method: :delete },
-        ) { "Delete" } %>
+    <%= render Components::ConfirmDialog.new(
+      variant: :destructive,
+      href: post_path(@post),
+      title: "Are you sure?",
+      description: "This action cannot be undone. This will permanently delete your post.",
+      action_text: "Delete post",
+      cancel_text: "Cancel",
+      data: { turbo_method: :delete },
+      ) { "Delete" } %>
   </div>
 </div>
diff --git a/db/migrate/20241017211831_add_organization_to_post.rb b/db/migrate/20241017211831_add_organization_to_post.rb
new file mode 100644
index 0000000..77ac39c
--- /dev/null
+++ b/db/migrate/20241017211831_add_organization_to_post.rb
@@ -0,0 +1,5 @@
+class AddOrganizationToPost < ActiveRecord::Migration[8.0]
+  def change
+    add_reference :posts, :organization, null: false, foreign_key: true
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 986301a..7c6ff99 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2024_10_16_231107) do
+ActiveRecord::Schema[8.0].define(version: 2024_10_17_211831) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_catalog.plpgsql"
 
@@ -73,6 +73,8 @@
     t.bigint "user_id", null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.bigint "organization_id", null: false
+    t.index ["organization_id"], name: "index_posts_on_organization_id"
     t.index ["user_id"], name: "index_posts_on_user_id"
   end
 
@@ -98,6 +100,7 @@
   add_foreign_key "active_storage_variant_records", "active_storage_blobs", column: "blob_id"
   add_foreign_key "memberships", "organizations"
   add_foreign_key "memberships", "users"
+  add_foreign_key "posts", "organizations"
   add_foreign_key "posts", "users"
   add_foreign_key "sessions", "users"
 end
diff --git a/test/controllers/posts_controller_test.rb b/test/controllers/posts_controller_test.rb
index f09bd1d..3d5de9e 100644
--- a/test/controllers/posts_controller_test.rb
+++ b/test/controllers/posts_controller_test.rb
@@ -13,11 +13,21 @@ class PostsControllerTest < ActionDispatch::IntegrationTest
 
       assert_response :success
     end
+
+    test "should only get posts for the current organization" do
+      organization = create(:organization)
+      user.organizations << organization
+      Current.stubs(:organization).returns(organization)
+
+      post = create(:post, organization: organization)
+      get posts_url
+
+      assert_includes assigns(:posts), post
+    end
   end # GET /posts
 
   describe "GET /posts/new" do
     test "should be successful" do
-      create(:user) # TODO: replace once authentication built
       get new_post_url
 
       assert_response :success
diff --git a/test/factories/memberships.rb b/test/factories/memberships.rb
index e19e39e..a306e6d 100644
--- a/test/factories/memberships.rb
+++ b/test/factories/memberships.rb
@@ -7,5 +7,9 @@
     trait :admin do
       role { :admin }
     end
+
+    trait :owner do
+      role { :owner }
+    end
   end
 end
diff --git a/test/factories/posts.rb b/test/factories/posts.rb
index dc8a384..07c5365 100644
--- a/test/factories/posts.rb
+++ b/test/factories/posts.rb
@@ -1,6 +1,7 @@
 FactoryBot.define do
   factory :post do
     user
+    organization
     title { "MyString" }
   end
 end
diff --git a/test/models/organization_test.rb b/test/models/organization_test.rb
index c1b2ef5..1e8e271 100644
--- a/test/models/organization_test.rb
+++ b/test/models/organization_test.rb
@@ -6,6 +6,7 @@ class OrganizationTest < ActiveSupport::TestCase
 
     should have_many(:memberships).dependent(:destroy)
     should have_many(:users).through(:memberships)
+    should have_many(:posts).dependent(:destroy)
   end
 
   describe "Validations" do
diff --git a/test/models/user_test.rb b/test/models/user_test.rb
index 755332f..787dc4a 100644
--- a/test/models/user_test.rb
+++ b/test/models/user_test.rb
@@ -33,4 +33,23 @@ class UserTest < ActiveSupport::TestCase
       assert_equal email.downcase, user.email_address
     end
   end
+
+  describe "Instance Methods" do
+    describe "#base_organization" do
+      it "should return the user's base organization" do
+        membership = create(:membership, :owner)
+        user = membership.user
+        assert_equal membership.organization, user.base_organization
+      end
+
+      it "should create a base organization if one does not exist" do
+        user = create(:user)
+        assert_difference("Organization.count", 1) do
+          assert_difference("Membership.count", 1) do
+            user.base_organization
+          end
+        end
+      end
+    end
+  end
 end