diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,8 @@
 # Changelog
 
+- 0.1.4 (2026-05-22)
+  * Adds variable-time comparison functions to Data.Word.Wider.
+
 - 0.1.3 (2025-12-28)
   * Makes some backward-incompatible API tweaks to Data.Choice:
 
diff --git a/lib/Data/Word/Wider.hs b/lib/Data/Word/Wider.hs
--- a/lib/Data/Word/Wider.hs
+++ b/lib/Data/Word/Wider.hs
@@ -32,6 +32,8 @@
   , lt#
   , gt
   , gt#
+  , lt_vartime
+  , gt_vartime
 
   -- * Parity
   , odd#
@@ -182,6 +184,22 @@
 lt (Wider a) (Wider b) = lt# a b
 {-# INLINABLE lt #-}
 
+-- | Variable-time less-than comparison between 'Wider' values.
+--
+--   >>> lt_vartime 1 2
+--   True
+--   >>> lt_vartime 2 1
+--   False
+lt_vartime :: Wider -> Wider -> Bool
+lt_vartime
+      (Wider (# Limb a0, Limb a1, Limb a2, Limb a3 #))
+      (Wider (# Limb b0, Limb b1, Limb b2, Limb b3 #))
+  | Exts.isTrue# (Exts.neWord# a3 b3) = Exts.isTrue# (Exts.ltWord# a3 b3)
+  | Exts.isTrue# (Exts.neWord# a2 b2) = Exts.isTrue# (Exts.ltWord# a2 b2)
+  | Exts.isTrue# (Exts.neWord# a1 b1) = Exts.isTrue# (Exts.ltWord# a1 b1)
+  | otherwise                         = Exts.isTrue# (Exts.ltWord# a0 b0)
+{-# INLINABLE lt_vartime #-}
+
 gt#
   :: Limb4
   -> Limb4
@@ -201,6 +219,16 @@
 gt :: Wider -> Wider -> C.Choice
 gt (Wider a) (Wider b) = gt# a b
 {-# INLINABLE gt #-}
+
+-- | Variable-time greater-than comparison between 'Wider' values.
+--
+--   >>> gt_vartime 1 2
+--   False
+--   >>> gt_vartime 2 1
+--   True
+gt_vartime :: Wider -> Wider -> Bool
+gt_vartime a b = lt_vartime b a
+{-# INLINABLE gt_vartime #-}
 
 cmp#
   :: Limb4
diff --git a/ppad-fixed.cabal b/ppad-fixed.cabal
--- a/ppad-fixed.cabal
+++ b/ppad-fixed.cabal
@@ -1,6 +1,6 @@
 cabal-version:      3.0
 name:               ppad-fixed
-version:            0.1.3
+version:            0.1.4
 synopsis:           Large fixed-width words and constant-time arithmetic.
 license:            MIT
 license-file:       LICENSE
diff --git a/test/Wider.hs b/test/Wider.hs
--- a/test/Wider.hs
+++ b/test/Wider.hs
@@ -102,6 +102,40 @@
   H.assertBool mempty (not (C.decide (W.lt# c a)))
   H.assertBool mempty (not (C.decide (W.lt# c b)))
 
+gt_vartime :: H.Assertion
+gt_vartime = do
+  let !a = 0
+      !b = 1
+      !c = 2 ^ (256 :: Word) - 1
+  H.assertBool mempty (W.gt_vartime b a)
+  H.assertBool mempty (W.gt_vartime c a)
+  H.assertBool mempty (W.gt_vartime c b)
+
+  H.assertBool mempty (not (W.gt_vartime a a))
+  H.assertBool mempty (not (W.gt_vartime b b))
+  H.assertBool mempty (not (W.gt_vartime c c))
+
+  H.assertBool mempty (not (W.gt_vartime a b))
+  H.assertBool mempty (not (W.gt_vartime a c))
+  H.assertBool mempty (not (W.gt_vartime b c))
+
+lt_vartime :: H.Assertion
+lt_vartime = do
+  let !a = 0
+      !b = 1
+      !c = 2 ^ (256 :: Word) - 1
+  H.assertBool mempty (W.lt_vartime a b)
+  H.assertBool mempty (W.lt_vartime a c)
+  H.assertBool mempty (W.lt_vartime b c)
+
+  H.assertBool mempty (not (W.lt_vartime a a))
+  H.assertBool mempty (not (W.lt_vartime b b))
+  H.assertBool mempty (not (W.lt_vartime c c))
+
+  H.assertBool mempty (not (W.lt_vartime b a))
+  H.assertBool mempty (not (W.lt_vartime c a))
+  H.assertBool mempty (not (W.lt_vartime c b))
+
 cmp :: H.Assertion
 cmp = do
   let !a = 0
@@ -149,6 +183,14 @@
 odd_correct :: W.Wider -> Bool
 odd_correct w = C.decide (W.odd w) == I.integerTestBit (W.from_vartime w) 0
 
+lt_vartime_correct :: W.Wider -> W.Wider -> Bool
+lt_vartime_correct a b =
+  W.lt_vartime a b == (W.from_vartime a < W.from_vartime b)
+
+gt_vartime_correct :: W.Wider -> W.Wider -> Bool
+gt_vartime_correct a b =
+  W.gt_vartime a b == (W.from_vartime a > W.from_vartime b)
+
 tests :: TestTree
 tests = testGroup "wider tests" [
     H.testCase "overflowing add, no carry" overflowing_add_no_carry
@@ -162,10 +204,16 @@
   , H.testCase "eq" eq
   , H.testCase "gt" gt
   , H.testCase "lt" lt
+  , H.testCase "gt_vartime" gt_vartime
+  , H.testCase "lt_vartime" lt_vartime
   , H.testCase "cmp" cmp
   , H.testCase "sqr" sqr
   , H.testCase "mul" mul
   , H.testCase "sub_mod" sub_mod
   , Q.testProperty "odd w ~ odd (from w)" $ Q.withMaxSuccess 500 odd_correct
+  , Q.testProperty "lt_vartime a b ~ from a < from b" $
+      Q.withMaxSuccess 500 lt_vartime_correct
+  , Q.testProperty "gt_vartime a b ~ from a > from b" $
+      Q.withMaxSuccess 500 gt_vartime_correct
   ]