diff --git a/repos/libports/recipes/raw/qt5_dejavusans/content.mk b/repos/libports/recipes/raw/qt5_dejavusans/content.mk
index 58a6ca5d77..f062b4f244 100644
--- a/repos/libports/recipes/raw/qt5_dejavusans/content.mk
+++ b/repos/libports/recipes/raw/qt5_dejavusans/content.mk
@@ -7,5 +7,5 @@ qt/lib/fonts/DejaVuSans.ttf:
 	cp $(PORT_DIR)/src/lib/qt5/qt5/qtquickcontrols/examples/quickcontrols/extras/dashboard/fonts/$(notdir $@) $@
 
 qt5_dejavusans.tar: qt/lib/fonts/DejaVuSans.ttf
-	tar cf $@ qt
+	tar cf $@ --mtime='1970-01-01' qt
 	rm -rf qt
diff --git a/repos/libports/recipes/raw/qt5_qt_labs_folderlistmodel/content.mk b/repos/libports/recipes/raw/qt5_qt_labs_folderlistmodel/content.mk
index ec0d9599c3..fac2d94a9b 100644
--- a/repos/libports/recipes/raw/qt5_qt_labs_folderlistmodel/content.mk
+++ b/repos/libports/recipes/raw/qt5_qt_labs_folderlistmodel/content.mk
@@ -12,5 +12,5 @@ $(QMLDIR): $(INSTALL_DIR)
 	cp $(PORT_DIR)/src/lib/qt5/qt5/qtdeclarative/src/imports/folderlistmodel/qmldir $@
 
 qt5_qt_labs_folderlistmodel.tar: $(QMLDIR)
-	tar cf $@ qt
+	tar cf $@ --mtime='1970-01-01' qt
 	rm -rf qt
diff --git a/repos/libports/recipes/raw/qt5_qtquick2/content.mk b/repos/libports/recipes/raw/qt5_qtquick2/content.mk
index 02e362607a..d56cf0c300 100644
--- a/repos/libports/recipes/raw/qt5_qtquick2/content.mk
+++ b/repos/libports/recipes/raw/qt5_qtquick2/content.mk
@@ -12,5 +12,5 @@ $(QMLDIR): $(INSTALL_DIR)
 	cp $(PORT_DIR)/src/lib/qt5/qt5/qtdeclarative/src/imports/qtquick2/qmldir $@
 
 qt5_qtquick2.tar: $(QMLDIR)
-	tar cf $@ qt
+	tar cf $@ --mtime='1970-01-01' qt
 	rm -rf qt
diff --git a/repos/libports/recipes/raw/qt5_qtquick_layouts/content.mk b/repos/libports/recipes/raw/qt5_qtquick_layouts/content.mk
index 5caf59f593..3479df6472 100644
--- a/repos/libports/recipes/raw/qt5_qtquick_layouts/content.mk
+++ b/repos/libports/recipes/raw/qt5_qtquick_layouts/content.mk
@@ -12,5 +12,5 @@ $(QMLDIR): $(INSTALL_DIR)
 	cp $(PORT_DIR)/src/lib/qt5/qt5/qtdeclarative/src/imports/layouts/qmldir $@
 
 qt5_qtquick_layouts.tar: $(QMLDIR)
-	tar cf $@ qt
+	tar cf $@ --mtime='1970-01-01' qt
 	rm -rf qt
diff --git a/repos/libports/recipes/raw/qt5_qtquick_virtualkeyboard/content.mk b/repos/libports/recipes/raw/qt5_qtquick_virtualkeyboard/content.mk
index 94a446cc15..8ab8c6d361 100644
--- a/repos/libports/recipes/raw/qt5_qtquick_virtualkeyboard/content.mk
+++ b/repos/libports/recipes/raw/qt5_qtquick_virtualkeyboard/content.mk
@@ -19,5 +19,5 @@ $(STYLES_QMLDIR): $(INSTALL_DIR)/Styles
 	cp $(PORT_DIR)/src/lib/qt5/qt5/qtvirtualkeyboard/src/virtualkeyboard/styles/qmldir $@
 
 qt5_qtquick_virtualkeyboard.tar: $(QMLDIR) $(STYLES_QMLDIR)
-	tar cf $@ qt
+	tar cf $@ --mtime='1970-01-01' qt
 	rm -rf qt
diff --git a/repos/libports/recipes/raw/qt5_qtquick_window/content.mk b/repos/libports/recipes/raw/qt5_qtquick_window/content.mk
index add9f6c98f..f260c5326a 100644
--- a/repos/libports/recipes/raw/qt5_qtquick_window/content.mk
+++ b/repos/libports/recipes/raw/qt5_qtquick_window/content.mk
@@ -12,5 +12,5 @@ $(QMLDIR): $(INSTALL_DIR)
 	cp $(PORT_DIR)/src/lib/qt5/qt5/qtdeclarative/src/imports/window/qmldir $@
 
 qt5_qtquick_window.tar: $(QMLDIR)
-	tar cf $@ qt
+	tar cf $@ --mtime='1970-01-01' qt
 	rm -rf qt
diff --git a/repos/libports/recipes/raw/qt5_samegame/content.mk b/repos/libports/recipes/raw/qt5_samegame/content.mk
index e422f5dba4..46bdd19178 100644
--- a/repos/libports/recipes/raw/qt5_samegame/content.mk
+++ b/repos/libports/recipes/raw/qt5_samegame/content.mk
@@ -29,5 +29,5 @@ $(addprefix samegame/shared/pics/, $(SAMEGAME_RESOURCES)): samegame/shared/pics
 
 qt5_samegame.tar: $(addprefix samegame/, $(SAMEGAME3_RESOURCES)) \
                   $(addprefix samegame/shared/pics/, $(SAMEGAME_RESOURCES))
-	tar cf $@ -C samegame .
+	tar cf $@ --mtime='1970-01-01' -C samegame .
 	rm -rf samegame/