diff --git a/lib/rscons/cli.rb b/lib/rscons/cli.rb
index 8ba2a50..3f6e230 100644
--- a/lib/rscons/cli.rb
+++ b/lib/rscons/cli.rb
@@ -166,6 +166,9 @@ EOF
       Task[].each do |name, task|
         if task.desc
           usage += %[  #{sprintf("%-27s", name)} #{task.desc}\n]
+          task.params.each do |name, param|
+            usage += %[    #{sprintf("%-25s", "--#{name}")} #{param.description}]
+          end
         end
       end
       usage
diff --git a/lib/rscons/script.rb b/lib/rscons/script.rb
index c9d253b..41f05fc 100644
--- a/lib/rscons/script.rb
+++ b/lib/rscons/script.rb
@@ -37,6 +37,18 @@ module Rscons
         end.sort
       end
 
+      # Construct a task parameter.
+      #
+      # @param name [String]
+      #   Param name.
+      # @param description [String]
+      #   Param description.
+      # @param value [String, nil]
+      #   Param value.
+      def param(name, description, value)
+        Task::Param.new(name, description, value)
+      end
+
       # Return path components from the PATH variable.
       #
       # @return [Array<String>]
diff --git a/lib/rscons/task.rb b/lib/rscons/task.rb
index e724f43..760e917 100644
--- a/lib/rscons/task.rb
+++ b/lib/rscons/task.rb
@@ -49,6 +49,37 @@ module Rscons
 
     end
 
+    # Class to represent a task parameter.
+    class Param
+
+      # @return [String]
+      #   Param name.
+      attr_reader :name
+
+      # @return [String]
+      #   Param description.
+      attr_reader :description
+
+      # @return [String, nil]
+      #   Param value.
+      attr_reader :value
+
+      # Construct a Param.
+      #
+      # @param name [String]
+      #   Param name.
+      # @param description [String]
+      #   Param description.
+      # @param value [String, nil]
+      #   Param value.
+      def initialize(name, description, value)
+        @name = name
+        @description = description
+        @value = value
+      end
+
+    end
+
     # @return [Boolean]
     #   Whether to automatically configure before running this task.
     attr_reader :autoconf
@@ -65,20 +96,26 @@ module Rscons
     #   Task name.
     attr_reader :name
 
+    # @return [Hash<String => Param>]
+    #   Task params.
+    attr_reader :params
+
     # Construct a task.
     #
     # @param name [String]
     #   Task name.
     # @param options [Hash]
-    #   Task options.
+    #   Options.
     # @option options [Boolean] :autoconf
     #   Whether to automatically configure before running this task (default
     #   true).
     def initialize(name, options, &block)
-      @name = name
-      @actions = []
-      @deps = []
       @autoconf = true
+      @deps = []
+      @desc = nil
+      @name = name
+      @params = {}
+      @actions = []
       Task.register(self)
       modify(options, &block)
     end
@@ -132,6 +169,11 @@ module Rscons
       if options.include?(:deps)
         @deps += options[:deps]
       end
+      if options.include?(:params)
+        options[:params].each do |param|
+          @params[param.name] = param
+        end
+      end
       if block
         if env = Environment.open_environment
           @actions << proc do