diff --git a/lib/uri/generic.rb b/lib/uri/generic.rb
index 6a0f638..779c855 100644
--- a/lib/uri/generic.rb
+++ b/lib/uri/generic.rb
@@ -1570,7 +1570,23 @@ def find_proxy(env=ENV)
     def self.use_proxy?(hostname, addr, port, no_proxy) # :nodoc:
       hostname = hostname.downcase
       dothostname = ".#{hostname}"
-      no_proxy.scan(/([^:,\s]+)(?::(\d+))?/) {|p_host, p_port|
+      no_proxy.split(/[,\s]+/).each {|entry|
+        next if entry.empty?
+        # Bracketed IPv6: [addr] or [addr]:port
+        if entry =~ /\A\[([^\]]+)\](?::(\d+))?\z/
+          p_port = $2  # read $2 before sub() clobbers global match variables
+          p_host = $1.sub(/%.*\z/, '')  # strip zone ID (e.g. [::1%eth0] -> ::1)
+        # Bare IPv6: address contains more than one colon (e.g. 2001:db8::1 or 2001:db8::/32)
+        elsif entry.count(':') > 1
+          p_host = entry.sub(/%.*\z/, '')  # strip zone ID (e.g. ::1%eth0 -> ::1)
+          p_port = nil
+        # IPv4 or hostname with optional port (trailing colon treated as no port)
+        elsif entry =~ /\A([^:]+)(?::(\d+)?)?\z/
+          p_host = $1
+          p_port = ($2 && !$2.empty?) ? $2 : nil
+        else
+          next
+        end
         if !p_port || port == p_port.to_i
           if p_host.start_with?('.')
             return false if hostname.end_with?(p_host.downcase)
@@ -1581,7 +1597,6 @@ def self.use_proxy?(hostname, addr, port, no_proxy) # :nodoc:
             begin
               return false if IPAddr.new(p_host).include?(addr)
             rescue IPAddr::InvalidAddressError
-              next
             end
           end
         end
diff --git a/test/uri/test_generic.rb b/test/uri/test_generic.rb
index 94eea71..d12880f 100644
--- a/test/uri/test_generic.rb
+++ b/test/uri/test_generic.rb
@@ -1020,6 +1020,26 @@ def test_use_proxy_p
       ['127.0.0.1', '127.0.0.1', 80, '10.224.0.0/22', true],
       ['10.224.1.1', '10.224.1.1', 80, '10.224.1.1', false],
       ['10.224.1.1', '10.224.1.1', 80, '10.224.0.0/22', false],
+      # IPv6: bare address in no_proxy
+      ['2001:db8::1', '2001:db8::1', 80, '2001:db8::1', false],
+      # IPv6: bracketed address in no_proxy
+      ['2001:db8::1', '2001:db8::1', 80, '[2001:db8::1]', false],
+      # IPv6: bracketed address with matching port
+      ['2001:db8::1', '2001:db8::1', 80, '[2001:db8::1]:80', false],
+      # IPv6: bracketed address with non-matching port
+      ['2001:db8::1', '2001:db8::1', 80, '[2001:db8::1]:443', true],
+      # IPv6: CIDR notation
+      ['2001:db8::1', '2001:db8::1', 80, '2001:db8::/32', false],
+      # IPv6: address not in no_proxy
+      ['2001:db8::2', '2001:db8::2', 80, '2001:db8::1', true],
+      # IPv6: multiple entries including IPv6
+      ['2001:db8::1', '2001:db8::1', 80, 'example.com,2001:db8::1', false],
+      # IPv6: zone ID stripped before matching (::1%eth0 should match ::1)
+      ['::1', '::1', 80, '::1%eth0', false],
+      # IPv6: zone ID stripped from bracketed form too ([::1%eth0]:80 should match ::1 on port 80)
+      ['::1', '::1', 80, '[::1%eth0]:80', false],
+      # Trailing colon treated as no-port (regression guard)
+      ['example.com', nil, 80, 'example.com:', false],
     ].each do |hostname, addr, port, no_proxy, expected|
       assert_equal expected, URI::Generic.use_proxy?(hostname, addr, port, no_proxy),
         "use_proxy?('#{hostname}', '#{addr}', #{port}, '#{no_proxy}')"