diff --git a/cpp/src/io/parquet/decode_fixed.cu b/cpp/src/io/parquet/decode_fixed.cu
index aaf5ebfbe7d..9acbe026bb2 100644
--- a/cpp/src/io/parquet/decode_fixed.cu
+++ b/cpp/src/io/parquet/decode_fixed.cu
@@ -848,6 +848,7 @@ inline __device__ void bool_plain_decode(page_state_s* s, state_buf* sb, int t,
 {
   int pos              = s->dict_pos;
   int const target_pos = pos + to_decode;
+  __syncthreads();  // Make sure all threads have read dict_pos before it changes at the end.
 
   while (pos < target_pos) {
     int const batch_len = min(target_pos - pos, decode_block_size_t);