diff --git a/index.js b/index.js
index dd53ec01..3a604fe9 100644
--- a/index.js
+++ b/index.js
@@ -3165,6 +3165,102 @@
                                   : Just(result.total / result.count);
       });
 
+  //# lt :: Ord a => a -> a -> Boolean
+  //.
+  //. Returns `true` if its first argument is smaller than its second
+  //. argument; `false` otherwise.
+  //.
+  //. Strings are compared lexicographically. Specifically, the Unicode
+  //. code point value of each character in the first string is compared
+  //. to the value of the corresponding character in the second string.
+  //.
+  //. See also [`lte`](#lte), [`gt`](#gt), and [`gte`](#gte).
+  //.
+  //. ```javascript
+  //. > S.lt(10, 2)
+  //. false
+  //.
+  //. > S.lt('10', '2')
+  //. true
+  //. ```
+  S.lt =
+  def('lt',
+      {a: [Ord]},
+      [a, a, $.Boolean],
+      function(x, y) { return x < y; });
+
+  //# lte :: Ord a => a -> a -> Boolean
+  //.
+  //. Returns `true` if its first argument is smaller than or equal to
+  //. its second argument; `false` otherwise.
+  //.
+  //. Strings are compared lexicographically. Specifically, the Unicode
+  //. code point value of each character in the first string is compared
+  //. to the value of the corresponding character in the second string.
+  //.
+  //. See also [`lt`](#lt), [`gt`](#gt), and [`gte`](#gte).
+  //.
+  //. ```javascript
+  //. > S.lte(10, 2)
+  //. false
+  //.
+  //. > S.lte('10', '2')
+  //. true
+  //. ```
+  S.lte =
+  def('lte',
+      {a: [Ord]},
+      [a, a, $.Boolean],
+      function(x, y) { return x <= y; });
+
+  //# gt :: Ord a => a -> a -> Boolean
+  //.
+  //. Returns `true` if its first argument is larger than its second
+  //. argument; `false` otherwise.
+  //.
+  //. Strings are compared lexicographically. Specifically, the Unicode
+  //. code point value of each character in the first string is compared
+  //. to the value of the corresponding character in the second string.
+  //.
+  //. See also [`gte`](#gte), [`lt`](#lt), and [`lte`](#lte).
+  //.
+  //. ```javascript
+  //. > S.gt(10, 2)
+  //. true
+  //.
+  //. > S.gt('10', '2')
+  //. false
+  //. ```
+  S.gt =
+  def('gt',
+      {a: [Ord]},
+      [a, a, $.Boolean],
+      function(x, y) { return x > y; });
+
+  //# gte :: Ord a => a -> a -> Boolean
+  //.
+  //. Returns `true` if its first argument is larger than or equal to
+  //. its second argument; `false` otherwise.
+  //.
+  //. Strings are compared lexicographically. Specifically, the Unicode
+  //. code point value of each character in the first string is compared
+  //. to the value of the corresponding character in the second string.
+  //.
+  //. See also [`gt`](#gt), [`lt`](#lt), and [`lte`](#lte).
+  //.
+  //. ```javascript
+  //. > S.gte(10, 2)
+  //. true
+  //.
+  //. > S.gte('10', '2')
+  //. false
+  //. ```
+  S.gte =
+  def('gte',
+      {a: [Ord]},
+      [a, a, $.Boolean],
+      function(x, y) { return x >= y; });
+
   //# min :: Ord a => a -> a -> a
   //.
   //. Returns the smaller of its two arguments.
diff --git a/test/gt.js b/test/gt.js
new file mode 100644
index 00000000..2053b4f3
--- /dev/null
+++ b/test/gt.js
@@ -0,0 +1,63 @@
+'use strict';
+
+var throws = require('assert').throws;
+
+var S = require('..');
+
+var eq = require('./internal/eq');
+var errorEq = require('./internal/errorEq');
+
+
+describe('gt', function() {
+
+  it('is a binary function', function() {
+    eq(typeof S.gt, 'function');
+    eq(S.gt.length, 2);
+  });
+
+  it('type checks its arguments', function() {
+    throws(function() { S.gt(null); },
+           errorEq(TypeError,
+                   'Type-class constraint violation\n' +
+                   '\n' +
+                   'gt :: Ord a => a -> a -> Boolean\n' +
+                   '      ^^^^^    ^\n' +
+                   '               1\n' +
+                   '\n' +
+                   '1)  null :: Null\n' +
+                   '\n' +
+                   '‘gt’ requires ‘a’ to satisfy the Ord type-class constraint; the value at position 1 does not.\n'));
+
+    throws(function() { S.gt('abc', 123); },
+           errorEq(TypeError,
+                   'Type-variable constraint violation\n' +
+                   '\n' +
+                   'gt :: Ord a => a -> a -> Boolean\n' +
+                   '               ^    ^\n' +
+                   '               1    2\n' +
+                   '\n' +
+                   '1)  "abc" :: String\n' +
+                   '\n' +
+                   '2)  123 :: Number, FiniteNumber, NonZeroFiniteNumber, Integer, ValidNumber\n' +
+                   '\n' +
+                   'Since there is no type of which all the above values are members, the type-variable constraint has been violated.\n'));
+  });
+
+  it('has > semantics', function() {
+    eq(S.gt(0, 0), false);
+    eq(S.gt(0, -0), false);
+    eq(S.gt(-0, 0), false);
+    eq(S.gt(-0, -0), false);
+    eq(S.gt(0, 1), false);
+    eq(S.gt(1, 0), true);
+    eq(S.gt(0, -1), true);
+    eq(S.gt(-1, 0), false);
+    eq(S.gt('a', 'a'), false);
+    eq(S.gt('a', 'z'), false);
+    eq(S.gt('z', 'a'), true);
+    eq(S.gt(new Date(0), new Date(0)), false);
+    eq(S.gt(new Date(0), new Date(1)), false);
+    eq(S.gt(new Date(1), new Date(0)), true);
+  });
+
+});
diff --git a/test/gte.js b/test/gte.js
new file mode 100644
index 00000000..5b07d3a5
--- /dev/null
+++ b/test/gte.js
@@ -0,0 +1,63 @@
+'use strict';
+
+var throws = require('assert').throws;
+
+var S = require('..');
+
+var eq = require('./internal/eq');
+var errorEq = require('./internal/errorEq');
+
+
+describe('gte', function() {
+
+  it('is a binary function', function() {
+    eq(typeof S.gte, 'function');
+    eq(S.gte.length, 2);
+  });
+
+  it('type checks its arguments', function() {
+    throws(function() { S.gte(null); },
+           errorEq(TypeError,
+                   'Type-class constraint violation\n' +
+                   '\n' +
+                   'gte :: Ord a => a -> a -> Boolean\n' +
+                   '       ^^^^^    ^\n' +
+                   '                1\n' +
+                   '\n' +
+                   '1)  null :: Null\n' +
+                   '\n' +
+                   '‘gte’ requires ‘a’ to satisfy the Ord type-class constraint; the value at position 1 does not.\n'));
+
+    throws(function() { S.gte('abc', 123); },
+           errorEq(TypeError,
+                   'Type-variable constraint violation\n' +
+                   '\n' +
+                   'gte :: Ord a => a -> a -> Boolean\n' +
+                   '                ^    ^\n' +
+                   '                1    2\n' +
+                   '\n' +
+                   '1)  "abc" :: String\n' +
+                   '\n' +
+                   '2)  123 :: Number, FiniteNumber, NonZeroFiniteNumber, Integer, ValidNumber\n' +
+                   '\n' +
+                   'Since there is no type of which all the above values are members, the type-variable constraint has been violated.\n'));
+  });
+
+  it('has >= semantics', function() {
+    eq(S.gte(0, 0), true);
+    eq(S.gte(0, -0), true);
+    eq(S.gte(-0, 0), true);
+    eq(S.gte(-0, -0), true);
+    eq(S.gte(0, 1), false);
+    eq(S.gte(1, 0), true);
+    eq(S.gte(0, -1), true);
+    eq(S.gte(-1, 0), false);
+    eq(S.gte('a', 'a'), true);
+    eq(S.gte('a', 'z'), false);
+    eq(S.gte('z', 'a'), true);
+    eq(S.gte(new Date(0), new Date(0)), true);
+    eq(S.gte(new Date(0), new Date(1)), false);
+    eq(S.gte(new Date(1), new Date(0)), true);
+  });
+
+});
diff --git a/test/lt.js b/test/lt.js
new file mode 100644
index 00000000..9c3955be
--- /dev/null
+++ b/test/lt.js
@@ -0,0 +1,63 @@
+'use strict';
+
+var throws = require('assert').throws;
+
+var S = require('..');
+
+var eq = require('./internal/eq');
+var errorEq = require('./internal/errorEq');
+
+
+describe('lt', function() {
+
+  it('is a binary function', function() {
+    eq(typeof S.lt, 'function');
+    eq(S.lt.length, 2);
+  });
+
+  it('type checks its arguments', function() {
+    throws(function() { S.lt(null); },
+           errorEq(TypeError,
+                   'Type-class constraint violation\n' +
+                   '\n' +
+                   'lt :: Ord a => a -> a -> Boolean\n' +
+                   '      ^^^^^    ^\n' +
+                   '               1\n' +
+                   '\n' +
+                   '1)  null :: Null\n' +
+                   '\n' +
+                   '‘lt’ requires ‘a’ to satisfy the Ord type-class constraint; the value at position 1 does not.\n'));
+
+    throws(function() { S.lt('abc', 123); },
+           errorEq(TypeError,
+                   'Type-variable constraint violation\n' +
+                   '\n' +
+                   'lt :: Ord a => a -> a -> Boolean\n' +
+                   '               ^    ^\n' +
+                   '               1    2\n' +
+                   '\n' +
+                   '1)  "abc" :: String\n' +
+                   '\n' +
+                   '2)  123 :: Number, FiniteNumber, NonZeroFiniteNumber, Integer, ValidNumber\n' +
+                   '\n' +
+                   'Since there is no type of which all the above values are members, the type-variable constraint has been violated.\n'));
+  });
+
+  it('has < semantics', function() {
+    eq(S.lt(0, 0), false);
+    eq(S.lt(0, -0), false);
+    eq(S.lt(-0, 0), false);
+    eq(S.lt(-0, -0), false);
+    eq(S.lt(0, 1), true);
+    eq(S.lt(1, 0), false);
+    eq(S.lt(0, -1), false);
+    eq(S.lt(-1, 0), true);
+    eq(S.lt('a', 'a'), false);
+    eq(S.lt('a', 'z'), true);
+    eq(S.lt('z', 'a'), false);
+    eq(S.lt(new Date(0), new Date(0)), false);
+    eq(S.lt(new Date(0), new Date(1)), true);
+    eq(S.lt(new Date(1), new Date(0)), false);
+  });
+
+});
diff --git a/test/lte.js b/test/lte.js
new file mode 100644
index 00000000..0ec43430
--- /dev/null
+++ b/test/lte.js
@@ -0,0 +1,63 @@
+'use strict';
+
+var throws = require('assert').throws;
+
+var S = require('..');
+
+var eq = require('./internal/eq');
+var errorEq = require('./internal/errorEq');
+
+
+describe('lte', function() {
+
+  it('is a binary function', function() {
+    eq(typeof S.lte, 'function');
+    eq(S.lte.length, 2);
+  });
+
+  it('type checks its arguments', function() {
+    throws(function() { S.lte(null); },
+           errorEq(TypeError,
+                   'Type-class constraint violation\n' +
+                   '\n' +
+                   'lte :: Ord a => a -> a -> Boolean\n' +
+                   '       ^^^^^    ^\n' +
+                   '                1\n' +
+                   '\n' +
+                   '1)  null :: Null\n' +
+                   '\n' +
+                   '‘lte’ requires ‘a’ to satisfy the Ord type-class constraint; the value at position 1 does not.\n'));
+
+    throws(function() { S.lte('abc', 123); },
+           errorEq(TypeError,
+                   'Type-variable constraint violation\n' +
+                   '\n' +
+                   'lte :: Ord a => a -> a -> Boolean\n' +
+                   '                ^    ^\n' +
+                   '                1    2\n' +
+                   '\n' +
+                   '1)  "abc" :: String\n' +
+                   '\n' +
+                   '2)  123 :: Number, FiniteNumber, NonZeroFiniteNumber, Integer, ValidNumber\n' +
+                   '\n' +
+                   'Since there is no type of which all the above values are members, the type-variable constraint has been violated.\n'));
+  });
+
+  it('has <= semantics', function() {
+    eq(S.lte(0, 0), true);
+    eq(S.lte(0, -0), true);
+    eq(S.lte(-0, 0), true);
+    eq(S.lte(-0, -0), true);
+    eq(S.lte(0, 1), true);
+    eq(S.lte(1, 0), false);
+    eq(S.lte(0, -1), false);
+    eq(S.lte(-1, 0), true);
+    eq(S.lte('a', 'a'), true);
+    eq(S.lte('a', 'z'), true);
+    eq(S.lte('z', 'a'), false);
+    eq(S.lte(new Date(0), new Date(0)), true);
+    eq(S.lte(new Date(0), new Date(1)), true);
+    eq(S.lte(new Date(1), new Date(0)), false);
+  });
+
+});