diff --git a/src/main/resources/templates/add-image.html b/src/main/resources/templates/add-image.html
index 4d80fb81..a83363ea 100644
--- a/src/main/resources/templates/add-image.html
+++ b/src/main/resources/templates/add-image.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<html th:lang="${#locale.language}" xmlns:th="http://www.thymeleaf.org">
 
 
 <th:block th:insert="~{fragments/common :: head(title=#{addImage.title})}"></th:block>
diff --git a/src/main/resources/templates/compress-pdf.html b/src/main/resources/templates/compress-pdf.html
index 5ae35ab6..98b7157b 100644
--- a/src/main/resources/templates/compress-pdf.html
+++ b/src/main/resources/templates/compress-pdf.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<html th:lang="${#locale.language}" xmlns:th="http://www.thymeleaf.org">
 
 
 <th:block th:insert="~{fragments/common :: head(title=#{compress.title})}"></th:block>
diff --git a/src/main/resources/templates/convert/img-to-pdf.html b/src/main/resources/templates/convert/img-to-pdf.html
index cdb5bc04..68d6d005 100644
--- a/src/main/resources/templates/convert/img-to-pdf.html
+++ b/src/main/resources/templates/convert/img-to-pdf.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<html th:lang="${#locale.language}" xmlns:th="http://www.thymeleaf.org">
 
 <th:block th:insert="~{fragments/common :: head(title=#{imageToPDF.title})}"></th:block>
 
diff --git a/src/main/resources/templates/convert/pdf-to-img.html b/src/main/resources/templates/convert/pdf-to-img.html
index 291507b3..a5008f90 100644
--- a/src/main/resources/templates/convert/pdf-to-img.html
+++ b/src/main/resources/templates/convert/pdf-to-img.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<html th:lang="${#locale.language}" xmlns:th="http://www.thymeleaf.org">
 
 <th:block th:insert="~{fragments/common :: head(title=#{pdfToImage})}"></th:block>
 
diff --git a/src/main/resources/templates/home.html b/src/main/resources/templates/home.html
index c8904f6b..50bdf4ff 100644
--- a/src/main/resources/templates/home.html
+++ b/src/main/resources/templates/home.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<html th:lang="${#locale.language}" xmlns:th="http://www.thymeleaf.org">
 
 
 <th:block th:insert="~{fragments/common :: head(title='')}"></th:block>
diff --git a/src/main/resources/templates/merge-pdfs.html b/src/main/resources/templates/merge-pdfs.html
index 2db124a4..bab357ae 100644
--- a/src/main/resources/templates/merge-pdfs.html
+++ b/src/main/resources/templates/merge-pdfs.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<html th:lang="${#locale.language}" xmlns:th="http://www.thymeleaf.org">
 
 <th:block th:insert="~{fragments/common :: head(title=#{merge.title})}"></th:block>
 
diff --git a/src/main/resources/templates/pdf-organizer.html b/src/main/resources/templates/pdf-organizer.html
index 01c5615c..0fa6037f 100644
--- a/src/main/resources/templates/pdf-organizer.html
+++ b/src/main/resources/templates/pdf-organizer.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<html th:lang="${#locale.language}" xmlns:th="http://www.thymeleaf.org">
 
 <th:block th:insert="~{fragments/common :: head(title=#{pdfOrganiser.title})}"></th:block>
 
diff --git a/src/main/resources/templates/remove-pages.html b/src/main/resources/templates/remove-pages.html
index ac6e573f..7d9fd38c 100644
--- a/src/main/resources/templates/remove-pages.html
+++ b/src/main/resources/templates/remove-pages.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<html th:lang="${#locale.language}" xmlns:th="http://www.thymeleaf.org">
 
 <th:block th:insert="~{fragments/common :: head(title=#{pageRemover.title})}"></th:block>
 
diff --git a/src/main/resources/templates/rotate-pdf.html b/src/main/resources/templates/rotate-pdf.html
index fb68049b..d4bfae95 100644
--- a/src/main/resources/templates/rotate-pdf.html
+++ b/src/main/resources/templates/rotate-pdf.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<html th:lang="${#locale.language}" xmlns:th="http://www.thymeleaf.org">
 
 
 <th:block th:insert="~{fragments/common :: head(title=#{rotate.title})}"></th:block>
diff --git a/src/main/resources/templates/security/add-password.html b/src/main/resources/templates/security/add-password.html
index fca33e65..858806b9 100644
--- a/src/main/resources/templates/security/add-password.html
+++ b/src/main/resources/templates/security/add-password.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<html th:lang="${#locale.language}" xmlns:th="http://www.thymeleaf.org">
 
 <th:block th:insert="~{fragments/common :: head(title=#{addPassword.title})}"></th:block>
 
diff --git a/src/main/resources/templates/security/add-watermark.html b/src/main/resources/templates/security/add-watermark.html
index 87974b32..2da5c29e 100644
--- a/src/main/resources/templates/security/add-watermark.html
+++ b/src/main/resources/templates/security/add-watermark.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<html th:lang="${#locale.language}" xmlns:th="http://www.thymeleaf.org">
 
 <th:block th:insert="~{fragments/common :: head(title=#{watermark.title})}"></th:block>
 
diff --git a/src/main/resources/templates/security/change-permissions.html b/src/main/resources/templates/security/change-permissions.html
index c8fd659b..80b531ad 100644
--- a/src/main/resources/templates/security/change-permissions.html
+++ b/src/main/resources/templates/security/change-permissions.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<html th:lang="${#locale.language}" xmlns:th="http://www.thymeleaf.org">
 
 <th:block th:insert="~{fragments/common :: head(title=#{permissions.title})}"></th:block>
 
diff --git a/src/main/resources/templates/security/remove-password.html b/src/main/resources/templates/security/remove-password.html
index 28fe91c6..720750c9 100644
--- a/src/main/resources/templates/security/remove-password.html
+++ b/src/main/resources/templates/security/remove-password.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<html th:lang="${#locale.language}" xmlns:th="http://www.thymeleaf.org">
 
 <th:block th:insert="~{fragments/common :: head(title=#{removePassword.title})}"></th:block>
 
diff --git a/src/main/resources/templates/split-pdfs.html b/src/main/resources/templates/split-pdfs.html
index bad209ac..79f22b37 100644
--- a/src/main/resources/templates/split-pdfs.html
+++ b/src/main/resources/templates/split-pdfs.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html lang="en" xmlns:th="http://www.thymeleaf.org">
+<html th:lang="${#locale.language}" xmlns:th="http://www.thymeleaf.org">
 
 <th:block th:insert="~{fragments/common :: head(title=#{split.title})}"></th:block>
 
