diff --git a/CHANGELOG.md b/CHANGELOG.md
index aec6d605a..cd9162efe 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ BUG FIXES:
   - core: private networks with DHCP type work if type parameter is
       a string and not a symbol. [GH-3349]
   - core: Converting to cygwin path works for folders with spaces. [GH-3304]
+  - core: Can add boxes with spaces in their path. [GH-3306]
   - commands/box: Show versions when listing. [GH-3316]
   - commands/status: Machine readable output contains the target. [GH-3218]
   - guests/arch: Reload udev rules after network change. [GH-3322]
diff --git a/lib/vagrant/action/builtin/box_add.rb b/lib/vagrant/action/builtin/box_add.rb
index 588ada093..c7c669bcc 100644
--- a/lib/vagrant/action/builtin/box_add.rb
+++ b/lib/vagrant/action/builtin/box_add.rb
@@ -30,7 +30,7 @@ module Vagrant
             u = u.gsub("\\", "/")
             if Util::Platform.windows? && u =~ /^[a-z]:/i
               # On Windows, we need to be careful about drive letters
-              u = "file://#{u}"
+              u = "file://#{URI.escape(u)}"
             end
 
             if u =~ /^[a-z0-9]+:.*$/i && !u.start_with?("file://")
@@ -39,9 +39,9 @@ module Vagrant
             end
 
             # Expand the path and try to use that, if possible
-            p = File.expand_path(u.gsub(/^file:\/\//, ""))
+            p = File.expand_path(URI.unescape(u.gsub(/^file:\/\//, "")))
             p = Util::Platform.cygwin_windows_path(p)
-            next "file://#{p.gsub("\\", "/")}" if File.file?(p)
+            next "file://#{URI.escape(p.gsub("\\", "/"))}" if File.file?(p)
 
             u
           end