diff --git a/app/chewy/accounts_index.rb b/app/chewy/accounts_index.rb
new file mode 100644
index 00000000000..e11b800394a
--- /dev/null
+++ b/app/chewy/accounts_index.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+class AccountsIndex < Chewy::Index
+  settings index: { refresh_interval: '5m' }, analysis: {
+    analyzer: {
+      content: {
+        tokenizer: 'whitespace',
+        filter: %w(lowercase asciifolding cjk_width),
+      },
+
+      edge_ngram: {
+        tokenizer: 'edge_ngram',
+        filter: %w(lowercase asciifolding cjk_width),
+      },
+    },
+
+    tokenizer: {
+      edge_ngram: {
+        type: 'edge_ngram',
+        min_gram: 1,
+        max_gram: 15,
+      },
+    },
+  }
+
+  define_type ::Account.searchable.includes(:account_stat), delete_if: ->(account) { account.destroyed? || !account.searchable? } do
+    root date_detection: false do
+      field :id, type: 'long'
+      field :display_name, type: 'text', analyzer: 'edge_ngram', search_analyzer: 'content'
+      field :acct, type: 'text', analyzer: 'edge_ngram', search_analyzer: 'content', value: ->(account) { [account.username, account.domain].compact.join('@') }
+      field :following_count, type: 'long', value: ->(account) { account.active_relationships.count }
+      field :followers_count, type: 'long', value: ->(account) { account.passive_relationships.count }
+      field :last_status_at, type: 'date', value: ->(account) { account.last_status_at || account.created_at }
+    end
+  end
+end
diff --git a/app/models/account.rb b/app/models/account.rb
index 60c06aaf0b4..392cc625fcc 100644
--- a/app/models/account.rb
+++ b/app/models/account.rb
@@ -127,6 +127,8 @@ class Account < ApplicationRecord
 
   delegate :chosen_languages, to: :user, prefix: false, allow_nil: true
 
+  update_index('accounts#account', :self) if Chewy.enabled?
+
   def local?
     domain.nil?
   end
@@ -169,6 +171,10 @@ class Account < ApplicationRecord
     subscription_expires_at.present?
   end
 
+  def searchable?
+    !(suspended? || moved?)
+  end
+
   def possibly_stale?
     last_webfingered_at.nil? || last_webfingered_at <= 1.day.ago
   end
diff --git a/app/models/account_stat.rb b/app/models/account_stat.rb
index 9813aa84ff1..6d1097cec68 100644
--- a/app/models/account_stat.rb
+++ b/app/models/account_stat.rb
@@ -16,6 +16,8 @@
 class AccountStat < ApplicationRecord
   belongs_to :account, inverse_of: :account_stat
 
+  update_index('accounts#account', :account) if Chewy.enabled?
+
   def increment_count!(key)
     update(attributes_for_increment(key))
   end
diff --git a/app/services/account_search_service.rb b/app/services/account_search_service.rb
index e1874d0450f..2d602a31dea 100644
--- a/app/services/account_search_service.rb
+++ b/app/services/account_search_service.rb
@@ -4,47 +4,150 @@ class AccountSearchService < BaseService
   attr_reader :query, :limit, :offset, :options, :account
 
   def call(query, account = nil, options = {})
-    @query   = query.strip
-    @limit   = options[:limit].to_i
-    @offset  = options[:offset].to_i
-    @options = options
-    @account = account
+    @acct_hint = query.start_with?('@')
+    @query     = query.strip.gsub(/\A@/, '')
+    @limit     = options[:limit].to_i
+    @offset    = options[:offset].to_i
+    @options   = options
+    @account   = account
 
-    search_service_results
+    search_service_results.compact.uniq
   end
 
   private
 
   def search_service_results
-    return [] if query_blank_or_hashtag? || limit < 1
+    return [] if query.blank? || limit < 1
 
-    if resolving_non_matching_remote_account?
-      [ResolveAccountService.new.call("#{query_username}@#{query_domain}")].compact
-    else
-      search_results_and_exact_match.compact.uniq
+    [exact_match] + search_results
+  end
+
+  def exact_match
+    return unless offset.zero? && username_complete?
+
+    return @exact_match if defined?(@exact_match)
+
+    @exact_match = begin
+      if options[:resolve]
+        ResolveAccountService.new.call(query)
+      elsif domain_is_local?
+        Account.find_local(query_username)
+      else
+        Account.find_remote(query_username, query_domain)
+      end
     end
   end
 
-  def resolving_non_matching_remote_account?
-    offset.zero? && options[:resolve] && !exact_match? && !domain_is_local?
+  def search_results
+    return [] if limit_for_non_exact_results.zero?
+
+    @search_results ||= begin
+      if Chewy.enabled?
+        from_elasticsearch
+      else
+        from_database
+      end
+    end
   end
 
-  def search_results_and_exact_match
-    return search_results.to_a unless offset.zero?
-
-    results = [exact_match]
-
-    return results if exact_match? && limit == 1
-
-    results + search_results.to_a
+  def from_database
+    if account
+      advanced_search_results
+    else
+      simple_search_results
+    end
   end
 
-  def query_blank_or_hashtag?
-    query.blank? || query.start_with?('#')
+  def advanced_search_results
+    Account.advanced_search_for(terms_for_query, account, limit_for_non_exact_results, options[:following], offset)
+  end
+
+  def simple_search_results
+    Account.search_for(terms_for_query, limit_for_non_exact_results, offset)
+  end
+
+  def from_elasticsearch
+    must_clauses   = [{ multi_match: { query: terms_for_query, fields: likely_acct? ? %w(acct) : %w(acct^2 display_name), type: 'best_fields' } }]
+    should_clauses = []
+
+    if account
+      return [] if options[:following] && following_ids.empty?
+
+      if options[:following]
+        must_clauses << { terms: { id: following_ids } }
+      elsif following_ids.any?
+        should_clauses << { terms: { id: following_ids, boost: 100 } }
+      end
+    end
+
+    query     = { bool: { must: must_clauses, should: should_clauses } }
+    functions = [reputation_score_function, followers_score_function, time_distance_function]
+
+    records = AccountsIndex.query(function_score: { query: query, functions: functions, boost_mode: 'multiply', score_mode: 'avg' })
+                           .limit(limit_for_non_exact_results)
+                           .offset(offset)
+                           .objects
+                           .compact
+
+    ActiveRecord::Associations::Preloader.new.preload(records, :account_stat)
+
+    records
+  end
+
+  def reputation_score_function
+    {
+      script_score: {
+        script: {
+          source: "(doc['followers_count'].value + 0.0) / (doc['followers_count'].value + doc['following_count'].value + 1)",
+        },
+      },
+    }
+  end
+
+  def followers_score_function
+    {
+      field_value_factor: {
+        field: 'followers_count',
+        modifier: 'log2p',
+        missing: 1,
+      },
+    }
+  end
+
+  def time_distance_function
+    {
+      gauss: {
+        last_status_at: {
+          scale: '30d',
+          offset: '30d',
+          decay: 0.3,
+        },
+      },
+    }
+  end
+
+  def following_ids
+    @following_ids ||= account.active_relationships.pluck(:target_account_id)
+  end
+
+  def limit_for_non_exact_results
+    if exact_match?
+      limit - 1
+    else
+      limit
+    end
+  end
+
+  def terms_for_query
+    if domain_is_local?
+      query_username
+    else
+      query
+    end
   end
 
   def split_query_string
-    @split_query_string ||= query.gsub(/\A@/, '').split('@')
+    @split_query_string ||= query.split('@')
   end
 
   def query_username
@@ -63,57 +166,15 @@ class AccountSearchService < BaseService
     @domain_is_local ||= TagManager.instance.local_domain?(query_domain)
   end
 
-  def search_from
-    options[:following] && account ? account.following : Account
-  end
-
   def exact_match?
     exact_match.present?
   end
 
-  def exact_match
-    return @exact_match if defined?(@exact_match)
-
-    @exact_match = begin
-      if domain_is_local?
-        search_from.without_suspended.find_local(query_username)
-      else
-        search_from.without_suspended.find_remote(query_username, query_domain)
-      end
-    end
+  def username_complete?
+    query.include?('@') && "@#{query}" =~ Account::MENTION_RE
   end
 
-  def search_results
-    @search_results ||= begin
-      if account
-        advanced_search_results
-      else
-        simple_search_results
-      end
-    end
-  end
-
-  def advanced_search_results
-    Account.advanced_search_for(terms_for_query, account, limit_for_non_exact_results, options[:following], offset)
-  end
-
-  def simple_search_results
-    Account.search_for(terms_for_query, limit_for_non_exact_results, offset)
-  end
-
-  def limit_for_non_exact_results
-    if offset.zero? && exact_match?
-      limit - 1
-    else
-      limit
-    end
-  end
-
-  def terms_for_query
-    if domain_is_local?
-      query_username
-    else
-      "#{query_username} #{query_domain}"
-    end
+  def likely_acct?
+    @acct_hint || username_complete?
   end
 end
diff --git a/spec/services/account_search_service_spec.rb b/spec/services/account_search_service_spec.rb
index 7b071b378e0..5b7182586c5 100644
--- a/spec/services/account_search_service_spec.rb
+++ b/spec/services/account_search_service_spec.rb
@@ -1,126 +1,56 @@
 require 'rails_helper'
 
 describe AccountSearchService, type: :service do
-  describe '.call' do
-    describe 'with a query to ignore' do
+  describe '#call' do
+    context 'with a query to ignore' do
       it 'returns empty array for missing query' do
         results = subject.call('', nil, limit: 10)
 
         expect(results).to eq []
       end
-      it 'returns empty array for hashtag query' do
-        results = subject.call('#tag', nil, limit: 10)
 
-        expect(results).to eq []
-      end
       it 'returns empty array for limit zero' do
         Fabricate(:account, username: 'match')
+
         results = subject.call('match', nil, limit: 0)
 
         expect(results).to eq []
       end
     end
 
-    describe 'searching for a simple term that is not an exact match' do
+    context 'searching for a simple term that is not an exact match' do
       it 'does not return a nil entry in the array for the exact match' do
-        match = Fabricate(:account, username: 'matchingusername')
-
+        account = Fabricate(:account, username: 'matchingusername')
         results = subject.call('match', nil, limit: 5)
-        expect(results).to eq [match]
+
+        expect(results).to eq [account]
       end
     end
 
-    describe 'searching local and remote users' do
-      describe "when only '@'" do
-        before do
-          allow(Account).to receive(:find_local)
-          allow(Account).to receive(:search_for)
-          subject.call('@', nil, limit: 10)
-        end
-
-        it 'uses find_local with empty query to look for local accounts' do
-          expect(Account).to have_received(:find_local).with('')
-        end
-      end
-
-      describe 'when no domain' do
-        before do
-          allow(Account).to receive(:find_local)
-          allow(Account).to receive(:search_for)
-          subject.call('one', nil, limit: 10)
-        end
-
-        it 'uses find_local to look for local accounts' do
-          expect(Account).to have_received(:find_local).with('one')
-        end
-
-        it 'uses search_for to find matches' do
-          expect(Account).to have_received(:search_for).with('one', 10, 0)
-        end
-      end
-
-      describe 'when there is a domain' do
-        before do
-          allow(Account).to receive(:find_remote)
-        end
-
-        it 'uses find_remote to look for remote accounts' do
-          subject.call('two@example.com', nil, limit: 10)
-          expect(Account).to have_received(:find_remote).with('two', 'example.com')
-        end
-
-        describe 'and there is no account provided' do
-          it 'uses search_for to find matches' do
-            allow(Account).to receive(:search_for)
-            subject.call('two@example.com', nil, limit: 10, resolve: false)
-
-            expect(Account).to have_received(:search_for).with('two example.com', 10, 0)
-          end
-        end
-
-        describe 'and there is an account provided' do
-          it 'uses advanced_search_for to find matches' do
-            account = Fabricate(:account)
-            allow(Account).to receive(:advanced_search_for)
-            subject.call('two@example.com', account, limit: 10, resolve: false)
-
-            expect(Account).to have_received(:advanced_search_for).with('two example.com', account, 10, nil, 0)
-          end
-        end
-      end
-    end
-
-    describe 'with an exact match' do
-      it 'returns exact match first, and does not return duplicates' do
-        partial = Fabricate(:account, username: 'exactness')
-        exact = Fabricate(:account, username: 'exact')
-
-        results = subject.call('exact', nil, limit: 10)
-        expect(results.size).to eq 2
-        expect(results).to eq [exact, partial]
-      end
-    end
-
-    describe 'when there is a local domain' do
+    context 'when there is a local domain' do
       around do |example|
         before = Rails.configuration.x.local_domain
+
         example.run
+
         Rails.configuration.x.local_domain = before
       end
 
       it 'returns exact match first' do
         remote     = Fabricate(:account, username: 'a', domain: 'remote', display_name: 'e')
         remote_too = Fabricate(:account, username: 'b', domain: 'remote', display_name: 'e')
-        exact = Fabricate(:account, username: 'e')
+        exact      = Fabricate(:account, username: 'e')
+
         Rails.configuration.x.local_domain = 'example.com'
 
         results = subject.call('e@example.com', nil, limit: 2)
+
         expect(results.size).to eq 2
         expect(results).to eq([exact, remote]).or eq([exact, remote_too])
       end
     end
 
-    describe 'when there is a domain but no exact match' do
+    context 'when there is a domain but no exact match' do
       it 'follows the remote account when resolve is true' do
         service = double(call: nil)
         allow(ResolveAccountService).to receive(:new).and_return(service)
@@ -138,23 +68,21 @@ describe AccountSearchService, type: :service do
       end
     end
 
-    describe 'should not include suspended accounts' do
-      it 'returns the fuzzy match first, and does not return suspended exacts' do
-        partial = Fabricate(:account, username: 'exactness')
-        exact = Fabricate(:account, username: 'exact', suspended: true)
+    it 'returns the fuzzy match first, and does not return suspended exacts' do
+      partial = Fabricate(:account, username: 'exactness')
+      exact   = Fabricate(:account, username: 'exact', suspended: true)
+      results = subject.call('exact', nil, limit: 10)
 
-        results = subject.call('exact', nil, limit: 10)
-        expect(results.size).to eq 1
-        expect(results).to eq [partial]
-      end
+      expect(results.size).to eq 1
+      expect(results).to eq [partial]
+    end
 
-      it "does not return suspended remote accounts" do
-        remote = Fabricate(:account, username: 'a', domain: 'remote', display_name: 'e', suspended: true)
+    it "does not return suspended remote accounts" do
+      remote  = Fabricate(:account, username: 'a', domain: 'remote', display_name: 'e', suspended: true)
+      results = subject.call('a@example.com', nil, limit: 2)
 
-        results = subject.call('a@example.com', nil, limit: 2)
-        expect(results.size).to eq 0
-        expect(results).to eq []
-      end
+      expect(results.size).to eq 0
+      expect(results).to eq []
     end
   end
 end