diff --git a/manifests/resource/server.pp b/manifests/resource/server.pp
index c6497642f..0fe501901 100644
--- a/manifests/resource/server.pp
+++ b/manifests/resource/server.pp
@@ -200,7 +200,7 @@
   Optional[String] $uwsgi                                                        = undef,
   Optional[String] $uwsgi_params                                                 = "${nginx::config::conf_dir}/uwsgi_params",
   Optional[String] $uwsgi_read_timeout                                           = undef,
-  Array $index_files                                                             = [
+  Optional[Array] $index_files                                                   = [
     'index.html',
     'index.htm',
     'index.php'],
diff --git a/spec/defines/resource_server_spec.rb b/spec/defines/resource_server_spec.rb
index 2ce119d84..02c2c3232 100644
--- a/spec/defines/resource_server_spec.rb
+++ b/spec/defines/resource_server_spec.rb
@@ -317,6 +317,18 @@
               attr: 'error_pages',
               value: { '503' => '/foo.html' },
               match: '  error_page  503 /foo.html;'
+            },
+            {
+              title: 'should set index_file(s)',
+              attr: 'index_files',
+              value: %w(name1 name2),
+              match: %r{\s*index\s+name1\s+name2;}
+            },
+            {
+              title: 'should not set index_file(s)',
+              attr: 'index_files',
+              value: :undef,
+              match: %r{^((?!index).)*$}
             }
           ].each do |param|
             context "when #{param[:attr]} is #{param[:value]}" do
@@ -733,6 +745,18 @@
               attr: 'use_default_location',
               value: true,
               notmatch: %r{  root /;}
+            },
+            {
+              title: 'should set index_file(s)',
+              attr: 'index_files',
+              value: %w(name1 name2),
+              match: %r{\s*index\s+name1\s+name2;}
+            },
+            {
+              title: 'should not set index_file(s)',
+              attr: 'index_files',
+              value: :undef,
+              match: %r{^((?!index).)*$}
             }
           ].each do |param|
             context "when #{param[:attr]} is #{param[:value]}" do
diff --git a/templates/server/server_header.erb b/templates/server/server_header.erb
index f4f91f985..0d26c3baf 100644
--- a/templates/server/server_header.erb
+++ b/templates/server/server_header.erb
@@ -145,7 +145,7 @@ server {
 <% if @ssl_redirect -%>
   return 301 https://$host<% if @_ssl_redirect_port.to_i != 443 %>:<%= @_ssl_redirect_port %><% end %>$request_uri;
 <% end -%>
-<% if @index_files.count > 0 and not @ssl_only -%>
+<% if @index_files and @index_files.count > 0 and not @ssl_only -%>
   index <% Array(@index_files).each do |i| %> <%= i %><% end %>;
 
 <% end -%>
diff --git a/templates/server/server_ssl_header.erb b/templates/server/server_ssl_header.erb
index e02838689..dc645de1e 100644
--- a/templates/server/server_ssl_header.erb
+++ b/templates/server/server_ssl_header.erb
@@ -81,7 +81,7 @@ server {
 <% if defined? @gzip_types -%>
   gzip_types <%= @gzip_types %>;
 <% end -%>
-<% if @index_files.count > 0 -%>
+<% if @index_files and @index_files.count > 0 -%>
   index <% Array(@index_files).each do |i| %> <%= i %><% end %>;
 
 <% end -%>