diff --git a/ExampleCodes/LinearSolvers/GMRES/Poisson/AMReX_GMRES_Poisson.H b/ExampleCodes/LinearSolvers/GMRES/Poisson/AMReX_GMRES_Poisson.H
index 73faaa86..61a5405c 100644
--- a/ExampleCodes/LinearSolvers/GMRES/Poisson/AMReX_GMRES_Poisson.H
+++ b/ExampleCodes/LinearSolvers/GMRES/Poisson/AMReX_GMRES_Poisson.H
@@ -1,5 +1,5 @@
-#ifndef AMREX_GMRES_MLMG_H_
-#define AMREX_GMRES_MLMG_H_
+#ifndef AMREX_GMRES_POISSON_H_
+#define AMREX_GMRES_POISSON_H_
 #include <AMReX_Config.H>
 
 #include <AMReX_GMRES.H>