diff --git a/stdlib/time/0/time.rbs b/stdlib/time/0/time.rbs
new file mode 100644
index 000000000..f99197fa5
--- /dev/null
+++ b/stdlib/time/0/time.rbs
@@ -0,0 +1,327 @@
+class Time
+  interface _TimeLike
+    def year: () -> Integer
+    def mon: () -> Integer
+    def day: () -> Integer
+  end
+
+  #
+  # Return the number of seconds the specified time zone differs
+  # from UTC.
+  #
+  # Numeric time zones that include minutes, such as
+  # <code>-10:00</code> or <code>+1330</code> will work, as will
+  # simpler hour-only time zones like <code>-10</code> or
+  # <code>+13</code>.
+  #
+  # Textual time zones listed in ZoneOffset are also supported.
+  #
+  # If the time zone does not match any of the above, +zone_offset+
+  # will check if the local time zone (both with and without
+  # potential Daylight Saving \Time changes being in effect) matches
+  # +zone+. Specifying a value for +year+ will change the year used
+  # to find the local time zone.
+  #
+  # If +zone_offset+ is unable to determine the offset, nil will be
+  # returned.
+  #
+  #     require 'time'
+  #
+  #     Time.zone_offset("EST") #=> -18000
+  #
+  # You must require 'time' to use this method.
+  #
+  def self.zone_offset: (String zone, ?Integer year) -> Integer
+
+  #
+  # Takes a string representation of a Time and attempts to parse it
+  # using a heuristic.
+  #
+  #     require 'time'
+  #
+  #     Time.parse("2010-10-31") #=> 2010-10-31 00:00:00 -0500
+  #
+  # Any missing pieces of the date are inferred based on the current date.
+  #
+  #     require 'time'
+  #
+  #     # assuming the current date is "2011-10-31"
+  #     Time.parse("12:00") #=> 2011-10-31 12:00:00 -0500
+  #
+  # We can change the date used to infer our missing elements by passing a second
+  # object that responds to #mon, #day and #year, such as Date, Time or DateTime.
+  # We can also use our own object.
+  #
+  #     require 'time'
+  #
+  #     class MyDate
+  #       attr_reader :mon, :day, :year
+  #
+  #       def initialize(mon, day, year)
+  #         @mon, @day, @year = mon, day, year
+  #       end
+  #     end
+  #
+  #     d  = Date.parse("2010-10-28")
+  #     t  = Time.parse("2010-10-29")
+  #     dt = DateTime.parse("2010-10-30")
+  #     md = MyDate.new(10,31,2010)
+  #
+  #     Time.parse("12:00", d)  #=> 2010-10-28 12:00:00 -0500
+  #     Time.parse("12:00", t)  #=> 2010-10-29 12:00:00 -0500
+  #     Time.parse("12:00", dt) #=> 2010-10-30 12:00:00 -0500
+  #     Time.parse("12:00", md) #=> 2010-10-31 12:00:00 -0500
+  #
+  # If a block is given, the year described in +date+ is converted
+  # by the block.  This is specifically designed for handling two
+  # digit years. For example, if you wanted to treat all two digit
+  # years prior to 70 as the year 2000+ you could write this:
+  #
+  #     require 'time'
+  #
+  #     Time.parse("01-10-31") {|year| year + (year < 70 ? 2000 : 1900)}
+  #     #=> 2001-10-31 00:00:00 -0500
+  #     Time.parse("70-10-31") {|year| year + (year < 70 ? 2000 : 1900)}
+  #     #=> 1970-10-31 00:00:00 -0500
+  #
+  # If the upper components of the given time are broken or missing, they are
+  # supplied with those of +now+.  For the lower components, the minimum
+  # values (1 or 0) are assumed if broken or missing.  For example:
+  #
+  #     require 'time'
+  #
+  #     # Suppose it is "Thu Nov 29 14:33:20 2001" now and
+  #     # your time zone is EST which is GMT-5.
+  #     now = Time.parse("Thu Nov 29 14:33:20 2001")
+  #     Time.parse("16:30", now)     #=> 2001-11-29 16:30:00 -0500
+  #     Time.parse("7/23", now)      #=> 2001-07-23 00:00:00 -0500
+  #     Time.parse("Aug 31", now)    #=> 2001-08-31 00:00:00 -0500
+  #     Time.parse("Aug 2000", now)  #=> 2000-08-01 00:00:00 -0500
+  #
+  # Since there are numerous conflicts among locally defined time zone
+  # abbreviations all over the world, this method is not intended to
+  # understand all of them.  For example, the abbreviation "CST" is
+  # used variously as:
+  #
+  #     -06:00 in America/Chicago,
+  #     -05:00 in America/Havana,
+  #     +08:00 in Asia/Harbin,
+  #     +09:30 in Australia/Darwin,
+  #     +10:30 in Australia/Adelaide,
+  #     etc.
+  #
+  # Based on this fact, this method only understands the time zone
+  # abbreviations described in RFC 822 and the system time zone, in the
+  # order named. (i.e. a definition in RFC 822 overrides the system
+  # time zone definition.)  The system time zone is taken from
+  # <tt>Time.local(year, 1, 1).zone</tt> and
+  # <tt>Time.local(year, 7, 1).zone</tt>.
+  # If the extracted time zone abbreviation does not match any of them,
+  # it is ignored and the given time is regarded as a local time.
+  #
+  # ArgumentError is raised if Date._parse cannot extract information from
+  # +date+ or if the Time class cannot represent specified date.
+  #
+  # This method can be used as a fail-safe for other parsing methods as:
+  #
+  #   Time.rfc2822(date) rescue Time.parse(date)
+  #   Time.httpdate(date) rescue Time.parse(date)
+  #   Time.xmlschema(date) rescue Time.parse(date)
+  #
+  # A failure of Time.parse should be checked, though.
+  #
+  # You must require 'time' to use this method.
+  #
+  def self.parse: (String date, ?_TimeLike now) ?{ (Integer) -> Integer } -> Time
+
+  #
+  # Works similar to +parse+ except that instead of using a
+  # heuristic to detect the format of the input string, you provide
+  # a second argument that describes the format of the string.
+  #
+  # If a block is given, the year described in +date+ is converted by the
+  # block.  For example:
+  #
+  #   Time.strptime(...) {|y| y < 100 ? (y >= 69 ? y + 1900 : y + 2000) : y}
+  #
+  # Below is a list of the formatting options:
+  #
+  # %a :: The abbreviated weekday name ("Sun")
+  # %A :: The  full  weekday  name ("Sunday")
+  # %b :: The abbreviated month name ("Jan")
+  # %B :: The  full  month  name ("January")
+  # %c :: The preferred local date and time representation
+  # %C :: Century (20 in 2009)
+  # %d :: Day of the month (01..31)
+  # %D :: Date (%m/%d/%y)
+  # %e :: Day of the month, blank-padded ( 1..31)
+  # %F :: Equivalent to %Y-%m-%d (the ISO 8601 date format)
+  # %g :: The last two digits of the commercial year
+  # %G :: The week-based year according to ISO-8601 (week 1 starts on Monday
+  #       and includes January 4)
+  # %h :: Equivalent to %b
+  # %H :: Hour of the day, 24-hour clock (00..23)
+  # %I :: Hour of the day, 12-hour clock (01..12)
+  # %j :: Day of the year (001..366)
+  # %k :: hour, 24-hour clock, blank-padded ( 0..23)
+  # %l :: hour, 12-hour clock, blank-padded ( 0..12)
+  # %L :: Millisecond of the second (000..999)
+  # %m :: Month of the year (01..12)
+  # %M :: Minute of the hour (00..59)
+  # %n :: Newline (\n)
+  # %N :: Fractional seconds digits
+  # %p :: Meridian indicator ("AM" or "PM")
+  # %P :: Meridian indicator ("am" or "pm")
+  # %r :: time, 12-hour (same as %I:%M:%S %p)
+  # %R :: time, 24-hour (%H:%M)
+  # %s :: Number of seconds since 1970-01-01 00:00:00 UTC.
+  # %S :: Second of the minute (00..60)
+  # %t :: Tab character (\t)
+  # %T :: time, 24-hour (%H:%M:%S)
+  # %u :: Day of the week as a decimal, Monday being 1. (1..7)
+  # %U :: Week number of the current year, starting with the first Sunday as
+  #       the first day of the first week (00..53)
+  # %v :: VMS date (%e-%b-%Y)
+  # %V :: Week number of year according to ISO 8601 (01..53)
+  # %W :: Week  number  of the current year, starting with the first Monday
+  #       as the first day of the first week (00..53)
+  # %w :: Day of the week (Sunday is 0, 0..6)
+  # %x :: Preferred representation for the date alone, no time
+  # %X :: Preferred representation for the time alone, no date
+  # %y :: Year without a century (00..99)
+  # %Y :: Year which may include century, if provided
+  # %z :: Time zone as  hour offset from UTC (e.g. +0900)
+  # %Z :: Time zone name
+  # %% :: Literal "%" character
+  # %+ :: date(1) (%a %b %e %H:%M:%S %Z %Y)
+  #
+  #     require 'time'
+  #
+  #     Time.strptime("2000-10-31", "%Y-%m-%d") #=> 2000-10-31 00:00:00 -0500
+  #
+  # You must require 'time' to use this method.
+  #
+  def self.strptime: (String date, String format, ?_TimeLike now) ?{ (Integer) -> Integer } -> Time
+
+  #
+  # Parses +date+ as date-time defined by RFC 2822 and converts it to a Time
+  # object.  The format is identical to the date format defined by RFC 822 and
+  # updated by RFC 1123.
+  #
+  # ArgumentError is raised if +date+ is not compliant with RFC 2822
+  # or if the Time class cannot represent specified date.
+  #
+  # See #rfc2822 for more information on this format.
+  #
+  #     require 'time'
+  #
+  #     Time.rfc2822("Wed, 05 Oct 2011 22:26:12 -0400")
+  #     #=> 2010-10-05 22:26:12 -0400
+  #
+  # You must require 'time' to use this method.
+  #
+  def self.rfc2822: (String date) -> Time
+
+  alias self.rfc822 self.rfc2822
+
+  #
+  # Parses +date+ as an HTTP-date defined by RFC 2616 and converts it to a
+  # Time object.
+  #
+  # ArgumentError is raised if +date+ is not compliant with RFC 2616 or if
+  # the Time class cannot represent specified date.
+  #
+  # See #httpdate for more information on this format.
+  #
+  #     require 'time'
+  #
+  #     Time.httpdate("Thu, 06 Oct 2011 02:26:12 GMT")
+  #     #=> 2011-10-06 02:26:12 UTC
+  #
+  # You must require 'time' to use this method.
+  #
+  def self.httpdate: (String date) -> Time
+
+  #
+  # Parses +date+ as a dateTime defined by the XML Schema and converts it to
+  # a Time object.  The format is a restricted version of the format defined
+  # by ISO 8601.
+  #
+  # ArgumentError is raised if +date+ is not compliant with the format or if
+  # the Time class cannot represent specified date.
+  #
+  # See #xmlschema for more information on this format.
+  #
+  #     require 'time'
+  #
+  #     Time.xmlschema("2011-10-05T22:26:12-04:00")
+  #     #=> 2011-10-05 22:26:12-04:00
+  #
+  # You must require 'time' to use this method.
+  #
+  def self.xmlschema: (String date) -> Time
+
+  alias self.iso8601 self.xmlschema
+
+  #
+  # Returns a string which represents the time as date-time defined by RFC 2822:
+  #
+  #   day-of-week, DD month-name CCYY hh:mm:ss zone
+  #
+  # where zone is [+-]hhmm.
+  #
+  # If +self+ is a UTC time, -0000 is used as zone.
+  #
+  #     require 'time'
+  #
+  #     t = Time.now
+  #     t.rfc2822  # => "Wed, 05 Oct 2011 22:26:12 -0400"
+  #
+  # You must require 'time' to use this method.
+  #
+  def rfc2822: () -> String
+
+  alias rfc822 rfc2822
+
+  #
+  # Returns a string which represents the time as RFC 1123 date of HTTP-date
+  # defined by RFC 2616:
+  #
+  #   day-of-week, DD month-name CCYY hh:mm:ss GMT
+  #
+  # Note that the result is always UTC (GMT).
+  #
+  #     require 'time'
+  #
+  #     t = Time.now
+  #     t.httpdate # => "Thu, 06 Oct 2011 02:26:12 GMT"
+  #
+  # You must require 'time' to use this method.
+  #
+  def httpdate: () -> String
+
+  #
+  # Returns a string which represents the time as a dateTime defined by XML
+  # Schema:
+  #
+  #   CCYY-MM-DDThh:mm:ssTZD
+  #   CCYY-MM-DDThh:mm:ss.sssTZD
+  #
+  # where TZD is Z or [+-]hh:mm.
+  #
+  # If self is a UTC time, Z is used as TZD.  [+-]hh:mm is used otherwise.
+  #
+  # +fractional_digits+ specifies a number of digits to use for fractional
+  # seconds.  Its default value is 0.
+  #
+  #     require 'time'
+  #
+  #     t = Time.now
+  #     t.iso8601  # => "2011-10-05T22:26:12-04:00"
+  #
+  # You must require 'time' to use this method.
+  #
+  def xmlschema: (?Integer fraction_digits) -> String
+
+  alias iso8601 xmlschema
+end
diff --git a/test/stdlib/TimeExtension_test.rb b/test/stdlib/TimeExtension_test.rb
new file mode 100644
index 000000000..49123ce0f
--- /dev/null
+++ b/test/stdlib/TimeExtension_test.rb
@@ -0,0 +1,119 @@
+require_relative "test_helper"
+require "time"
+
+class TimeExtensionSingletonTest < Minitest::Test
+  include TypeAssertions
+
+  library "time"
+  testing "singleton(::Time)"
+
+  class MyDate
+    attr_reader :mon, :day, :year
+
+    def initialize(mon, day, year)
+      @mon, @day, @year = mon, day, year
+    end
+  end
+
+  def test_zone_offset
+    assert_send_type "(String) -> Integer",
+                     Time, :zone_offset, "EST"
+    assert_send_type "(String, Integer) -> Integer",
+                     Time, :zone_offset, "EST", 100
+  end
+
+  def test_parse
+    assert_send_type "(String) -> Time",
+                     Time, :parse, "2010-10-31"
+    assert_send_type "(String, Date) -> Time",
+                     Time, :parse, "12:00", Date.parse("2010-10-28")
+    assert_send_type "(String, Time) -> Time",
+                     Time, :parse, "12:00", Time.parse("2010-10-29")
+    assert_send_type "(String, DateTime) -> Time",
+                     Time, :parse, "12:00", DateTime.parse("2010-10-30")
+    assert_send_type "(String, TimeExtensionSingletonTest::MyDate) -> Time",
+                     Time, :parse, "12:00", MyDate.new(10, 31, 2010)
+    assert_send_type "(String) { (Integer) -> Integer } -> Time",
+                     Time, :parse, "01-10-31" do |year| year + 1000 end
+    assert_send_type "(String, Date) { (Integer) -> Integer } -> Time",
+                     Time, :parse, "12:00", Date.parse("2010-10-28") do |year| year + 1000 end
+  end
+
+  def test_strptime
+    assert_send_type "(String, String) -> Time",
+                     Time, :strptime, "2010-10-31", "%Y-%m-%d"
+    assert_send_type "(String, String, Date) -> Time",
+                     Time, :strptime, "12:00", "%H:%M", Date.parse("2010-10-28")
+    assert_send_type "(String, String, Time) -> Time",
+                     Time, :strptime, "12:00", "%H:%M", Time.parse("2010-10-29")
+    assert_send_type "(String, String, DateTime) -> Time",
+                     Time, :strptime, "12:00", "%H:%M", DateTime.parse("2010-10-30")
+    assert_send_type "(String, String, TimeExtensionSingletonTest::MyDate) -> Time",
+                     Time, :strptime, "12:00", "%H:%M", MyDate.new(10, 31, 2010)
+    assert_send_type "(String, String) { (Integer) -> Integer } -> Time",
+                     Time, :strptime, "01-10-31", "%y-%m-%d" do |year| year + 1000 end
+    assert_send_type "(String, String, Date) { (Integer) -> Integer } -> Time",
+                     Time, :strptime, "12:00", "%H:%M", Date.parse("2010-10-28") do |year| year + 1000 end
+  end
+
+  def test_rfc2822
+    assert_send_type "(String) -> Time",
+                     Time, :rfc2822, "Wed, 05 Oct 2011 22:26:12 -0400"
+  end
+
+  def test_rfc822
+    assert_send_type "(String) -> Time",
+                     Time, :rfc822, "Wed, 05 Oct 2011 22:26:12 -0400"
+  end
+
+  def test_httpdate
+    assert_send_type "(String) -> Time",
+                     Time, :httpdate, "Thu, 06 Oct 2011 02:26:12 GMT"
+  end
+
+  def test_xmlschema
+    assert_send_type "(String) -> Time",
+                     Time, :xmlschema, "2011-10-05T22:26:12-04:00"
+  end
+
+  def test_iso8601
+    assert_send_type "(String) -> Time",
+                     Time, :iso8601, "2011-10-05T22:26:12-04:00"
+  end
+end
+
+class TimeExtensionInstanceTest < Minitest::Test
+  include TypeAssertions
+
+  library "time"
+  testing "::Time"
+
+  def test_rfc2822
+    assert_send_type "() -> String",
+                     Time.now, :rfc2822
+  end
+
+  def test_rfc822
+    assert_send_type "() -> String",
+                     Time.now, :rfc822
+  end
+
+  def test_httpdate
+    assert_send_type "() -> String",
+                     Time.now, :httpdate
+  end
+
+  def test_xmlschema
+    assert_send_type "() -> String",
+                     Time.now, :xmlschema
+    assert_send_type "(Integer) -> String",
+                     Time.now, :xmlschema, 3
+  end
+
+  def test_iso8601
+    assert_send_type "() -> String",
+                     Time.now, :iso8601
+    assert_send_type "(Integer) -> String",
+                     Time.now, :iso8601, 3
+  end
+end