diff --git a/CHANGELOG.md b/CHANGELOG.md
index 68111d542..2918d0bcf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,8 @@ IMPROVEMENTS:
   - core: Multiple SSH keys can be specified with `config.ssh.private_key_path`
     [GH-907]
   - core: `config.vm.box_url` can be an array of URLs. [GH-1958]
+  - commands/box/add: Can now specify a custom CA cert for verifying
+    certs from a custom CA. [GH-2337]
   - commands/box/add: Can now specify a client cert when downloading a
     box. [GH-1889]
   - commands/init: Add `--output` option for specifing output path, or
diff --git a/lib/vagrant/action/builtin/box_add.rb b/lib/vagrant/action/builtin/box_add.rb
index c0906e7f6..8f3897dfa 100644
--- a/lib/vagrant/action/builtin/box_add.rb
+++ b/lib/vagrant/action/builtin/box_add.rb
@@ -106,6 +106,7 @@ module Vagrant
           end
 
           downloader_options = {}
+          downloader_options[:ca_cert] = env[:box_download_ca_cert]
           downloader_options[:continue] = true
           downloader_options[:insecure] = env[:box_download_insecure]
           downloader_options[:ui] = env[:ui]
diff --git a/lib/vagrant/util/downloader.rb b/lib/vagrant/util/downloader.rb
index e6e7d4250..6f26447d0 100644
--- a/lib/vagrant/util/downloader.rb
+++ b/lib/vagrant/util/downloader.rb
@@ -20,6 +20,7 @@ module Vagrant
 
         # Get the various optional values
         options     ||= {}
+        @ca_cert     = options[:ca_cert]
         @continue    = options[:continue]
         @insecure    = options[:insecure]
         @ui          = options[:ui]
@@ -42,6 +43,7 @@ module Vagrant
           "--output", @destination,
         ]
 
+        options += ["--cacert", @ca_cert] if @ca_cert
         options += ["--continue-at", "-"] if @continue
         options << "--insecure" if @insecure
         options << "--cert" << @client_cert if @client_cert
diff --git a/plugins/commands/box/command/add.rb b/plugins/commands/box/command/add.rb
index c5817dc32..3099c6c37 100644
--- a/plugins/commands/box/command/add.rb
+++ b/plugins/commands/box/command/add.rb
@@ -23,6 +23,10 @@ module VagrantPlugins
               options[:insecure] = i
             end
 
+            o.on("--cacert certfile", String, "CA certificate") do |c|
+              options[:ca_cert] = c
+            end
+
             o.on("--cert certfile", String,
                  "The client SSL cert") do |c|
               options[:client_cert] = c
@@ -49,6 +53,7 @@ module VagrantPlugins
             :box_url      => argv[1],
             :box_clean    => options[:clean],
             :box_force    => options[:force],
+            :box_download_ca_cert => options[:ca_cert],
             :box_download_client_cert => options[:client_cert],
             :box_download_insecure => options[:insecure],
           })
diff --git a/website/docs/source/v2/cli/box.html.md b/website/docs/source/v2/cli/box.html.md
index a1e0e2f5e..178054136 100644
--- a/website/docs/source/v2/cli/box.html.md
+++ b/website/docs/source/v2/cli/box.html.md
@@ -38,6 +38,9 @@ after the initial download.
 
 ## Options
 
+* `--cacert CERTFILE` - The certificate for the CA used to verify the peer.
+  This should be used if the remote end doesn't use a standard root CA.
+
 * `--cert CERTFILE` - A client certificate to use when downloading the box, if
   necessary.