diff --git a/mfbt/Compression.cpp b/mfbt/Compression.cpp
index e0018dd05095..5d093b9bf406 100644
--- a/mfbt/Compression.cpp
+++ b/mfbt/Compression.cpp
@@ -37,13 +37,6 @@ size_t LZ4::compressLimitedOutput(const char* aSource, size_t aInputSize,
                               maxOutputSizeChecked.value());
 }
 
-bool LZ4::decompress(const char* aSource, char* aDest, size_t aOutputSize) {
-  CheckedInt<int> outputSizeChecked = aOutputSize;
-  MOZ_ASSERT(outputSizeChecked.isValid());
-  int ret = LZ4_decompress_fast(aSource, aDest, outputSizeChecked.value());
-  return ret >= 0;
-}
-
 bool LZ4::decompress(const char* aSource, size_t aInputSize, char* aDest,
                      size_t aMaxOutputSize, size_t* aOutputSize) {
   CheckedInt<int> maxOutputSizeChecked = aMaxOutputSize;
diff --git a/mfbt/Compression.h b/mfbt/Compression.h
index 9a6e5b955fa4..1ed93c1220d6 100644
--- a/mfbt/Compression.h
+++ b/mfbt/Compression.h
@@ -64,22 +64,6 @@ class LZ4 {
                                                size_t aInputSize, char* aDest,
                                                size_t aMaxOutputSize);
 
-  /**
-   * If the source stream is malformed, the function will stop decoding
-   * and return false.
-   *
-   * This function never writes outside of provided buffers, and never
-   * modifies input buffer.
-   *
-   * Note: destination buffer must be already allocated, and its size must be a
-   *       minimum of |aOutputSize| bytes.
-   *
-   * @param aOutputSize is the output size, therefore the original size
-   * @return true on success, false on failure
-   */
-  static MFBT_API MOZ_MUST_USE bool decompress(const char* aSource, char* aDest,
-                                               size_t aOutputSize);
-
   /**
    * If the source stream is malformed, the function will stop decoding
    * and return false.