diff --git a/ground/openpilotgcs/src/libs/eigen/Eigen/align-function.h b/ground/openpilotgcs/src/libs/eigen/Eigen/align-function.h
index 160fdc33b..7b4599fb0 100644
--- a/ground/openpilotgcs/src/libs/eigen/Eigen/align-function.h
+++ b/ground/openpilotgcs/src/libs/eigen/Eigen/align-function.h
@@ -4,7 +4,7 @@
 /*
  * The purpose of this macro is to force the alignment of the stack to a
  * 16-byte boundary on systems that don't provide it automatically.  At
- * this time, only GCC on Win32 is know to require it.  MSVC on Win32 may
+ * this time, only GCC on Win32 is known to require it.  MSVC on Win32 may
  * as well.
  */