diff --git a/Userland/Libraries/LibCompress/Brotli.cpp b/Userland/Libraries/LibCompress/Brotli.cpp
index 6221bc15f7..e9cf773f96 100644
--- a/Userland/Libraries/LibCompress/Brotli.cpp
+++ b/Userland/Libraries/LibCompress/Brotli.cpp
@@ -11,7 +11,7 @@
 
 namespace Compress {
 
-ErrorOr<size_t> BrotliDecompressionStream::CanonicalCode::read_symbol(LittleEndianInputBitStream& input_stream)
+ErrorOr<size_t> BrotliDecompressionStream::CanonicalCode::read_symbol(LittleEndianInputBitStream& input_stream) const
 {
     size_t code_bits = 1;
 
diff --git a/Userland/Libraries/LibCompress/Brotli.h b/Userland/Libraries/LibCompress/Brotli.h
index e1bbe00350..43ccb5f524 100644
--- a/Userland/Libraries/LibCompress/Brotli.h
+++ b/Userland/Libraries/LibCompress/Brotli.h
@@ -31,7 +31,7 @@ public:
 
     public:
         CanonicalCode() = default;
-        ErrorOr<size_t> read_symbol(LittleEndianInputBitStream&);
+        ErrorOr<size_t> read_symbol(LittleEndianInputBitStream&) const;
         void clear()
         {
             m_symbol_codes.clear();