diff --git a/build/check.xsl b/build/check.xsl
index 5855e2f4..3d23a5ae 100644
--- a/build/check.xsl
+++ b/build/check.xsl
@@ -269,6 +269,20 @@
 			<xsl:with-param name="m">Scope <xsl:value-of select="."/> lacks @regexp</xsl:with-param>
 		</xsl:call-template>
 	</xsl:template>
+
+
+	<!--
+		Check for empty xml:lang elements, automatically generated by OIOSAML.
+		
+		This is not schema-valid so would be caught further down the line anyway,
+		but it's nice to have a clear error message earlier in the process.
+	-->
+	<xsl:template match="@xml:lang[.='']">
+		<xsl:call-template name="fatal">
+			<xsl:with-param name="m">empty xml:lang attribute</xsl:with-param>
+		</xsl:call-template>
+	</xsl:template>
+
 
 
 	<!--
diff --git a/build/check_imported.xsl b/build/check_imported.xsl
index 180bcfb9..00aeb60e 100644
--- a/build/check_imported.xsl
+++ b/build/check_imported.xsl
@@ -196,6 +196,19 @@
 	</xsl:template>
 	
 	
+	<!--
+		Check for empty xml:lang elements, automatically generated by OIOSAML.
+		
+		This is not schema-valid so would be caught further down the line anyway,
+		but it's nice to have a clear error message earlier in the process.
+	-->
+	<xsl:template match="@xml:lang[.='']">
+		<xsl:call-template name="fatal">
+			<xsl:with-param name="m">empty xml:lang attribute</xsl:with-param>
+		</xsl:call-template>
+	</xsl:template>
+	
+	
 	<!--
 		Common template to call to report a fatal error on some element within an entity.
 	-->