diff --git a/tachyon/math/polynomial/polynomials/univariate/sparse_coefficients.h b/tachyon/math/polynomial/polynomials/univariate/sparse_coefficients.h
index 9134d8aa9c..1a0e92ee2e 100644
--- a/tachyon/math/polynomial/polynomials/univariate/sparse_coefficients.h
+++ b/tachyon/math/polynomial/polynomials/univariate/sparse_coefficients.h
@@ -9,6 +9,7 @@
 #include <vector>
 
 #include "absl/numeric/internal/bits.h"
+#include "absl/types/span.h"
 
 #include "tachyon/base/containers/adapters.h"
 #include "tachyon/base/logging.h"