diff --git a/app/abilities/ability.rb b/app/abilities/ability.rb
index 195f1be4ac9..09027998047 100644
--- a/app/abilities/ability.rb
+++ b/app/abilities/ability.rb
@@ -68,7 +68,7 @@ def initialize(user)
         can [:edit, :update], Community, user_is_community_organizer
         can [:edit, :create, :destroy, :new, :update], CommunityLink, { :community => user_is_community_organizer }
         can [:create, :destroy], CommunityMember, { :user_id => user.id }
-        can [:edit, :update], CommunityMember, { :community => user_is_community_organizer }
+        can [:destroy, :edit, :update], CommunityMember, { :community => user_is_community_organizer }
 
         if user.moderator?
           can [:hide, :hidecomment], DiaryEntry
diff --git a/app/controllers/community_members_controller.rb b/app/controllers/community_members_controller.rb
index eb05d7aca0d..3a39ae8bdcf 100644
--- a/app/controllers/community_members_controller.rb
+++ b/app/controllers/community_members_controller.rb
@@ -1,7 +1,7 @@
 class CommunityMembersController < ApplicationController
   layout "site"
   before_action :authorize_web
-  before_action :set_community_member, :only => [:edit, :update]
+  before_action :set_community_member, :only => [:destroy, :edit, :update]
   load_and_authorize_resource :except => [:create, :new]
   authorize_resource
 
@@ -40,6 +40,18 @@ def update
     end
   end
 
+  def destroy
+    issues = @community_member.can_be_deleted
+    if issues.empty? && @community_member.destroy
+      redirect_to @community_member.community, :notice => t(".success")
+    else
+      issues = issues.map { |i| t("activerecord.errors.models.community_member.#{i}") }
+      issues = issues.to_sentence.capitalize
+      flash[:error] = "#{t('.failure')} #{issues}."
+      redirect_to community_community_members_path(@community_member.community)
+    end
+  end
+
   private
 
   def set_community_member
diff --git a/app/models/community.rb b/app/models/community.rb
index 7b12d46c522..2566dabdbc5 100644
--- a/app/models/community.rb
+++ b/app/models/community.rb
@@ -26,7 +26,7 @@ class Community < ApplicationRecord
   friendly_id :name, :use => :slugged
 
   # Organizers before members, a tad hacky, but works for now.
-  has_many :community_members, -> { order(:role => :desc) }, :inverse_of => :community
+  has_many :community_members, -> { order(:user_id) }, :inverse_of => :community
   has_many :users, :through => :community_members # TODO: counter_cache
 
   belongs_to :leader, :class_name => "User"
diff --git a/app/models/community_member.rb b/app/models/community_member.rb
index 7b8811a81ec..51e6eaed7a5 100644
--- a/app/models/community_member.rb
+++ b/app/models/community_member.rb
@@ -26,9 +26,21 @@ module Roles
   belongs_to :community
   belongs_to :user
 
+  scope :organizers, -> { where(:role => Roles::ORGANIZER) }
+  scope :members, -> { where(:role => Roles::MEMBER) }
+
   validates :community, :associated => true
   validates :user, :associated => true
   validates :role, :inclusion => { :in => Roles::ALL_ROLES }
 
   # TODO: validate uniqueness of user's role in each community.
+
+  # We assume this user already belongs to this community.
+  def can_be_deleted
+    issues = []
+    # The user may also be an organizer under a separate membership.
+    issues.append(:is_organizer) if CommunityMember.exists?(:community_id => community_id, :user_id => user_id, :role => Roles::ORGANIZER)
+
+    issues
+  end
 end
diff --git a/app/views/communities/show.html.erb b/app/views/communities/show.html.erb
index 99c679337f0..18c80f043e4 100644
--- a/app/views/communities/show.html.erb
+++ b/app/views/communities/show.html.erb
@@ -59,11 +59,17 @@
         <% end %>
       </div>
       <div>
-        <% if current_user && ! @community.member?(current_user) %>
-          <%= bootstrap_form_for @current_user_membership do |form| %>
-            <%= form.hidden_field(:community_id) %>
-            <%= form.hidden_field(:user_id) %>
-            <%= form.primary t(".join.action") %>
+        <% if current_user %>
+          <% if ! @community.member?(current_user) %>
+            <%= bootstrap_form_for @current_user_membership do |form| %>
+              <%= form.hidden_field(:community_id) %>
+              <%= form.hidden_field(:user_id) %>
+              <%= form.primary t(".join.action") %>
+            <% end %>
+          <% else %>
+            <%= bootstrap_form_for @current_user_membership, :method => :delete do |form| %>
+              <%= form.primary t(".leave.action"), :data => { :confirm => t(".leave.confirm", :name => @community.name) } %>
+            <% end %>
           <% end %>
         <% else %>
           <div>
diff --git a/app/views/community_members/index.html.erb b/app/views/community_members/index.html.erb
index ff2876ff736..5d2d7f2e809 100644
--- a/app/views/community_members/index.html.erb
+++ b/app/views/community_members/index.html.erb
@@ -25,6 +25,11 @@
                   <%= form.primary t(".edit") %>
                 <% end %>
               </div>
+              <div class="col-1">
+                <%= bootstrap_form_for membership, :method => :delete, :url => community_member_path(membership) do |form| %>
+                  <%= form.submit t(".remove") %>
+                <% end %>
+              </div>
             <% end %>
           </div>
         </li>
diff --git a/config/locales/en.yml b/config/locales/en.yml
index cf2546e53e7..7110b3d955e 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -60,11 +60,15 @@ en:
         invalid_email_address: does not appear to be a valid e-mail address
         email_address_not_routable: is not routable
         url: "is not a valid secure URL"
+      models:
+        community_member:
+          is_organizer: "you are an organizer of this community"
     # Translates all the model names, which is used in error handling on the website
     models:
       acl: "Access Control List"
       changeset: "Changeset"
       changeset_tag: "Changeset Tag"
+      community: "Community"
       country: "Country"
       diary_comment: "Diary Comment"
       diary_entry: "Diary Entry"
@@ -531,6 +535,9 @@ en:
       join:
         action: "Join"
         confirm: "Join %{name}?"
+      leave:
+        action: "Leave"
+        confirm: "Are you sure you want to leave %{name}?"
       links: "Links"
       login_to_join: "Please login to join the community."
       members: "Members"
@@ -550,6 +557,9 @@ en:
     create:
       failure: The community member could not be created.
       success: Member was successfully created.
+    destroy:
+      failure: Member was not removed.
+      success: Member was removed.
     edit:
       edit_member: Editing Member
     index:
@@ -557,6 +567,7 @@ en:
       member: Member
       members: Members
       organizers: Organizers
+      remove: remove
     update:
       failure: Community Member could not be updated.
       success: Community Member was successfully updated.
diff --git a/config/routes.rb b/config/routes.rb
index 03c11d65ad9..4f1bd4e12a7 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -333,7 +333,7 @@
   end
   post "/communities/:id/step_up" => "communities#step_up", :as => :step_up, :id => /\d+/
   resources :community_links, :only => [:destroy, :edit, :update]
-  resources :community_members, :only => [:create, :edit, :new, :update]
+  resources :community_members, :only => [:create, :destroy, :edit, :new, :update]
   get "/community_members" => "community_members#create", :as => "login_to_join"
 
   # errors
diff --git a/test/controllers/community_members_controller_test.rb b/test/controllers/community_members_controller_test.rb
index a9ea2d66b08..8224561fb5f 100644
--- a/test/controllers/community_members_controller_test.rb
+++ b/test/controllers/community_members_controller_test.rb
@@ -131,4 +131,63 @@ def test_update_when_save_fails
     assert_response :success
     assert_template "community_members/edit"
   end
+
+  def test_delete_as_a_different_user
+    # arrange
+    cm = create(:community_member) # N.b. not an organizer
+    session_for(create(:user))
+
+    # act
+    delete community_member_url(cm), :xhr => true
+
+    # assert
+    follow_redirect!
+    assert_response :forbidden
+  end
+
+  def test_delete_when_destroy_works
+    # arrange
+    cm1 = create(:community_member, :organizer) # original
+    session_for(cm1.user)
+    cm2 = create(:community_member, :community => cm1.community)
+
+    # act
+    delete community_member_url(cm2), :xhr => true
+
+    # assert
+    cm1.reload
+    assert_not cm1.community.member?(cm2.user)
+  end
+
+  def test_delete_when_destroy_fails
+    # arrange
+    cm = create(:community_member, :organizer)
+    session_for(cm.user)
+    # Customize this instance so delete returns false.
+    def cm.destroy
+      false
+    end
+
+    controller_mock = CommunityMembersController.new
+    def controller_mock.set_community_member
+      @community_member = CommunityMember.new
+    end
+
+    def controller_mock.render(_partial, _msg)
+      # Can't do assert_equal here.
+      # assert_equal :edit, partial
+    end
+
+    # act
+    CommunityMembersController.stub :new, controller_mock do
+      CommunityMember.stub :new, cm do
+        assert_difference "CommunityMember.count", 0 do
+          delete community_member_url(cm), :xhr => true
+        end
+      end
+    end
+
+    # assert
+    assert_match(/#{I18n.t("community_members.destroy.failure")}/, flash[:error])
+  end
 end