diff --git a/Changelog.md b/Changelog.md
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,3 +1,15 @@
+# 1.2.0
+
+## Major Changes
+
+- `withFDHandler` now explicitly flushes the file handle whenever log entries
+   are rendered out. Thanks to @filterfish for identifying this omission that
+   could lead to log messages being dropped.
+
+   Upgrade steps: no changes other than updating `logging-effect`.
+
+---
+
 # 1.1.3
 
 ## Other Changes
@@ -49,7 +61,7 @@
   severity. The combinators are: `logDebug`, `logInfo`, `logNotice`,
   `logWarning`, `logError`, `logCritical`, `logAlert` and `logEmergency`.
 
-- `mapLogMessage` got a companion function `mapLogMessageM` that works with 
+- `mapLogMessage` got a companion function `mapLogMessageM` that works with
   monadic tranformations.
 
 *Other*
diff --git a/logging-effect.cabal b/logging-effect.cabal
--- a/logging-effect.cabal
+++ b/logging-effect.cabal
@@ -1,5 +1,5 @@
 name: logging-effect
-version: 1.1.3
+version: 1.2.0
 synopsis: A mtl-style monad transformer for general purpose & compositional logging
 homepage: https://github.com/ocharles/logging-effect
 license: BSD3
diff --git a/src/Control/Monad/Log.hs b/src/Control/Monad/Log.hs
--- a/src/Control/Monad/Log.hs
+++ b/src/Control/Monad/Log.hs
@@ -100,7 +100,7 @@
 #else
 import GHC.Stack (SrcLoc, CallStack, getCallStack, prettySrcLoc)
 #endif
-import System.IO (Handle)
+import System.IO (Handle, hFlush)
 import qualified Data.Text.Lazy as LT
 import qualified Text.PrettyPrint.Leijen.Text as PP
 import qualified Data.List.NonEmpty as NEL
@@ -527,9 +527,16 @@
   -> Int -- ^ The amount of characters per line. Lines longer than this will be pretty-printed across multiple lines if possible.
   -> (Handler io PP.Doc -> io a)
   -> io a
-withFDHandler options fd ribbonFrac width =
-  withBatchedHandler options
-                     (PP.displayIO fd . PP.renderPretty ribbonFrac width . (<> PP.linebreak) . PP.vsep . NEL.toList)
+withFDHandler options fd ribbonFrac width = withBatchedHandler options flush
+  where
+    flush messages = do
+      PP.displayIO
+        fd
+        (PP.renderPretty
+           ribbonFrac
+           width
+           (PP.vsep (NEL.toList messages) <> PP.linebreak))
+      hFlush fd
 
 --------------------------------------------------------------------------------
 -- | A 'MonadLog' handler optimised for pure usage. Log messages are accumulated