diff --git a/app/controllers/bets_controller.rb b/app/controllers/bets_controller.rb
new file mode 100644
index 0000000..cc6e250
--- /dev/null
+++ b/app/controllers/bets_controller.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+class BetsController < ApplicationController
+  before_action :set_match, only: %i[index create]
+  before_action :authenticate_user!, only: %i[create]
+  rescue_from UserServiceError, with: :handle_user_service_error
+
+  def index
+    render json: @match.bets.group_by(&:team).map { |team, bets|
+      {
+        team: ActiveModelSerializers::SerializableResource.new(team).as_json,
+        bets: bets.size
+      }
+    }
+  end
+
+  def create
+    render json: user_service.bet!(@match, Team.find_by(id: params[:team]))
+  end
+
+  private
+
+  def user_service
+    @user_service ||= UserService.new current_user
+  end
+
+  def set_match
+    @match = Match.find params[:match_id]
+  end
+
+  def handle_user_service_error(exception)
+    render json: { error: exception.message }, status: :unprocessable_entity
+  end
+end
diff --git a/app/errors/user_service_error.rb b/app/errors/user_service_error.rb
new file mode 100644
index 0000000..9ef94df
--- /dev/null
+++ b/app/errors/user_service_error.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class UserServiceError < StandardError
+end
diff --git a/app/models/bet.rb b/app/models/bet.rb
new file mode 100644
index 0000000..d9a736d
--- /dev/null
+++ b/app/models/bet.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Bet < ApplicationRecord
+  belongs_to :user
+  belongs_to :match
+  belongs_to :team, optional: true
+end
diff --git a/app/models/match.rb b/app/models/match.rb
index bc80977..7891276 100644
--- a/app/models/match.rb
+++ b/app/models/match.rb
@@ -5,7 +5,9 @@ class Match < ApplicationRecord
 
   belongs_to :stage, optional: true
   belongs_to :group, optional: true
+
   has_many :match_scores, dependent: :destroy
+  has_many :bets, dependent: :destroy
 
   validates :match_scores, length: { maximum: 2 }
 
diff --git a/app/models/team.rb b/app/models/team.rb
index f266f9c..d81563e 100644
--- a/app/models/team.rb
+++ b/app/models/team.rb
@@ -4,6 +4,7 @@ class Team < ApplicationRecord
   belongs_to :tournament, optional: true
   has_many :group_scores, dependent: :destroy
   has_many :match_scores, dependent: :destroy
+  has_many :bets, dependent: :destroy
 
   validates :name, presence: true
 
diff --git a/app/models/user.rb b/app/models/user.rb
index a45995e..c21ab22 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -11,4 +11,5 @@ class User < ApplicationRecord
   validates :username, presence: true, uniqueness: { case_sensitive: false }
 
   has_many :tournaments, dependent: :destroy
+  has_many :bets, dependent: :destroy
 end
diff --git a/app/serializers/bet_serializer.rb b/app/serializers/bet_serializer.rb
new file mode 100644
index 0000000..9dc798e
--- /dev/null
+++ b/app/serializers/bet_serializer.rb
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class BetSerializer < ApplicationSerializer
+  belongs_to :match
+  belongs_to :team
+end
diff --git a/app/services/user_service.rb b/app/services/user_service.rb
new file mode 100644
index 0000000..f950f0e
--- /dev/null
+++ b/app/services/user_service.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class UserService
+  def initialize(user)
+    @user = user
+  end
+
+  def bet!(match, team)
+    validate_bet! match, team
+    @user.bets.create! match: match, team: team
+  end
+
+  private
+
+  def validate_bet!(match, team)
+    if team.nil?
+      raise UserServiceError, 'Betting on no team in a playoff match is not supported' unless match.group_match?
+    else
+      raise UserServiceError, 'The given team is not involved in the given match' unless match.teams.include? team
+    end
+    raise UserServiceError, 'This user already created a bet on this match' if match.bets.map(&:user).include? @user
+    raise UserServiceError, "Betting is not allowed while match is #{match.state}" \
+      unless %w[not_ready not_started].include? match.state
+  end
+end
diff --git a/config/routes.rb b/config/routes.rb
index 63c742d..d8f761a 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -6,7 +6,9 @@ Rails.application.routes.draw do
     sessions: 'overrides/sessions'
   }
 
-  resources :matches, only: %i[show update]
+  resources :matches, only: %i[show update] do
+    resources :bets, only: %i[index create]
+  end
   resources :teams, only: %i[show update]
   resources :tournaments do
     resources :statistics, only: %i[index]
diff --git a/db/migrate/0001_create_bets.rb b/db/migrate/0001_create_bets.rb
new file mode 100644
index 0000000..08b83ea
--- /dev/null
+++ b/db/migrate/0001_create_bets.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class CreateBets < ActiveRecord::Migration[5.2]
+  def change
+    create_table :bets do |t|
+      t.references :user, index: true, null: false, foreign_key: { on_delete: :cascade }
+      t.references :match, index: true, null: false, foreign_key: { on_delete: :cascade }
+      t.references :team, index: true, null: true, foreign_key: { on_delete: :cascade }
+
+      t.timestamps
+    end
+  end
+end
diff --git a/spec/controllers/bets_controller_spec.rb b/spec/controllers/bets_controller_spec.rb
new file mode 100644
index 0000000..8587bb2
--- /dev/null
+++ b/spec/controllers/bets_controller_spec.rb
@@ -0,0 +1,91 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe BetsController, type: :controller do
+  let(:team) do
+    create(:team)
+  end
+
+  let(:match) do
+    match = create(:playoff_match)
+    match.bets << create(:bet, team: team)
+    match
+  end
+
+  let(:params) do
+    {
+      match_id: match.to_param
+    }
+  end
+
+  describe 'GET #index' do
+    it 'returns a list of bet counts' do
+      get :index, params: params
+      body = deserialize_response response
+      expect(body.size).to eq(1)
+      expect(body.first[:team][:id]).to eq(team.id)
+      expect(body.first[:bets]).to eq(1)
+    end
+  end
+
+  describe 'POST #create' do
+    let(:create_params) do
+      params.merge(team: team.to_param)
+    end
+
+    let(:user_service) do
+      instance_double('UserService')
+    end
+
+    before do
+      allow(controller).to receive(:user_service).and_return(user_service)
+    end
+
+    context 'without authentication headers' do
+      it 'renders an unauthorized error response' do
+        post :create, params: params
+        expect(response).to have_http_status(:unauthorized)
+      end
+    end
+
+    context 'with authentication headers' do
+      before(:each) do
+        apply_authentication_headers_for create(:user)
+      end
+
+      it 'returns the created bet' do
+        bet = create(:bet)
+        expect(user_service).to receive(:bet!).and_return(bet)
+        post :create, params: create_params
+        expect(response).to be_successful
+        body = deserialize_response(response)
+        expect(body[:id]).to eq(bet.id)
+      end
+
+      context 'given a team' do
+        it 'calls the service' do
+          expect(user_service).to receive(:bet!).with(match, team)
+          post :create, params: create_params
+        end
+      end
+
+      context 'given no team' do
+        it 'calls the service' do
+          expect(user_service).to receive(:bet!).with(match, nil)
+          post :create, params: params.merge(team: nil)
+        end
+      end
+
+      context 'on service exception' do
+        it 'returns an error response' do
+          msg = 'an error'
+          expect(user_service).to receive(:bet!).and_raise(UserServiceError, msg)
+          post :create, params: create_params
+          expect(response).to have_http_status(:unprocessable_entity)
+          expect(deserialize_response(response)[:error]).to eq(msg)
+        end
+      end
+    end
+  end
+end
diff --git a/spec/factories/bets.rb b/spec/factories/bets.rb
new file mode 100644
index 0000000..6cc28df
--- /dev/null
+++ b/spec/factories/bets.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+FactoryBot.define do
+  factory :bet do
+    user
+    team
+    match
+  end
+end
diff --git a/spec/models/bet_spec.rb b/spec/models/bet_spec.rb
new file mode 100644
index 0000000..06e7a78
--- /dev/null
+++ b/spec/models/bet_spec.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Bet, type: :model do
+  describe 'association' do
+    it { should belong_to :user }
+    it { should belong_to :match }
+    it { should belong_to(:team).optional }
+  end
+end
diff --git a/spec/models/match_spec.rb b/spec/models/match_spec.rb
index 1491bfa..6610b96 100644
--- a/spec/models/match_spec.rb
+++ b/spec/models/match_spec.rb
@@ -5,6 +5,7 @@ require 'rails_helper'
 RSpec.describe Match, type: :model do
   context 'association' do
     it { should have_many :match_scores }
+    it { should have_many :bets }
     it { should belong_to(:stage).optional }
     it { should belong_to(:group).optional }
   end
diff --git a/spec/models/team_spec.rb b/spec/models/team_spec.rb
index c2f25e3..d6d097e 100644
--- a/spec/models/team_spec.rb
+++ b/spec/models/team_spec.rb
@@ -11,5 +11,6 @@ RSpec.describe Team, type: :model do
     it { should belong_to(:tournament).optional }
     it { should have_many :group_scores }
     it { should have_many :match_scores }
+    it { should have_many :bets }
   end
 end
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index 7216b64..83ab130 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -5,6 +5,7 @@ require 'rails_helper'
 RSpec.describe User, type: :model do
   describe 'association' do
     it { should have_many :tournaments }
+    it { should have_many :bets }
   end
 
   describe 'validation' do
diff --git a/spec/services/user_service_spec.rb b/spec/services/user_service_spec.rb
new file mode 100644
index 0000000..b0e8c22
--- /dev/null
+++ b/spec/services/user_service_spec.rb
@@ -0,0 +1,89 @@
+# frozen_string_literal: true
+
+RSpec.describe UserService do
+  let(:user) do
+    create(:user)
+  end
+
+  let(:user_service) do
+    UserService.new(user)
+  end
+
+  let(:team) do
+    create(:team)
+  end
+
+  def build_match(involved_team = team, factory = :playoff_match)
+    create(factory, state: :not_started, match_scores: [create(:match_score, team: involved_team)])
+  end
+
+  describe '#bet!' do
+    context 'with an unrelated team' do
+      it 'throws an exception' do
+        expect do
+          user_service.bet! build_match(create(:team)), team
+        end.to raise_error(UserServiceError, 'The given team is not involved in the given match')
+      end
+    end
+
+    context 'on a running match' do
+      it 'throws an exception' do
+        match = build_match
+        match.state = :in_progress
+        expect do
+          user_service.bet! match, team
+        end.to raise_error(UserServiceError, 'Betting is not allowed while match is in_progress')
+      end
+    end
+
+    context 'with an existing team' do
+      let(:match) do
+        build_match
+      end
+
+      let!(:bet) do
+        user_service.bet! match, team
+      end
+
+      it 'associates the bet with the given team' do
+        expect(team.bets.reload).to include(bet)
+      end
+
+      it 'associates the bet with the given match' do
+        expect(match.bets.reload).to include(bet)
+      end
+
+      it 'associates the bet with the creating user' do
+        expect(user.bets.reload).to include(bet)
+      end
+
+      context 'with an already existing bet' do
+        it 'throws an exception' do
+          match = build_match
+          user_service.bet! match, team
+          user.reload
+          match.reload
+          expect do
+            user_service.bet! match, team
+          end.to raise_error(UserServiceError, 'This user already created a bet on this match')
+        end
+      end
+    end
+
+    context 'without a team' do
+      context 'on a playoff stage' do
+        it 'throws an exception' do
+          expect do
+            user_service.bet! build_match, nil
+          end.to raise_error(UserServiceError, 'Betting on no team in a playoff match is not supported')
+        end
+      end
+
+      context 'on a group stage' do
+        it 'succeeds' do
+          user_service.bet! build_match(team, :group_match), nil
+        end
+      end
+    end
+  end
+end