diff --git a/bip-segwit-gbt.mediawiki b/bip-segwit-gbt.mediawiki
index 75b5097a..0ad10c28 100644
--- a/bip-segwit-gbt.mediawiki
+++ b/bip-segwit-gbt.mediawiki
@@ -59,7 +59,7 @@ Servers MUST NOT include a commitment in the "coinbasetxn" key on the template.
 
 ==Motivation==
 
-Segregated witness substatially changes the structure of blocks, so the previous getblocktemplate specification is no longer sufficient.
+Segregated witness substantially changes the structure of blocks, so the previous getblocktemplate specification is no longer sufficient.
 It additionally also adds a new way of counting resource limits, and so GBT must be extended to convey this information correctly as well.
 
 ==Rationale==