diff --git a/aegisub/Makefile.target b/aegisub/Makefile.target
index 491398938..04730b151 100644
--- a/aegisub/Makefile.target
+++ b/aegisub/Makefile.target
@@ -1,7 +1,6 @@
 #  *** THERE ARE NO USER-EDITABLE ITEMS HERE. ***
 #
 # TODO:
-#       * DESTDIR= support for make install.
 #       * Allow variables to be overridden on the CL.
 
 .PHONY: all install clean subdirs $(SUBDIRS)
@@ -66,30 +65,30 @@ install: $(SUBDIRS) install-share install-program install-lib
 
 install-program:
 ifdef PROGRAM_INSTALL
-	@$(BIN_MKDIR) -p $(P_BINDIR)
-	@$(BIN_INSTALL) $(PROGRAM) $(P_BINDIR)/$(PROGRAM)
+	@$(BIN_MKDIR) -p $(DESTDIR)$(P_BINDIR)
+	@$(BIN_INSTALL) $(PROGRAM) $(DESTDIR)$(P_BINDIR)/$(PROGRAM)
 endif
 
 install-lib:
 ifdef LIB_SHARED_INSTALL
-	$(BIN_MKDIR) -p $(P_LIB)
-	$(BIN_INSTALL) $(LIB_SHARED_FULL) $(P_LIB)/$(LIB_SHARED_FULL)
-	$(BIN_LN) -sf $(LIB_SHARED_FULL) $(P_LIB)/$(LIB_SHARED)
+	$(BIN_MKDIR) -p $(DESTDIR)$(P_LIB)
+	$(BIN_INSTALL) $(LIB_SHARED_FULL) $(DESTDIR)$(P_LIB)/$(LIB_SHARED_FULL)
+	$(BIN_LN) -sf $(LIB_SHARED_FULL) $(DESTDIR)$(P_LIB)/$(LIB_SHARED)
 endif
 
 install-share:
 ifdef DATA_SHARE
-	@$(BIN_MKDIR) -p $(addprefix $(P_DATA)/, $(dir $(DATA_SHARE)))
+	@$(BIN_MKDIR) -p $(addprefix $(DESTDIR)$(P_DATA)/, $(dir $(DATA_SHARE)))
 	@for i in $(DATA_SHARE); do \
-		$(BIN_ECHO) "$(BIN_INSTALL) $$i $(P_DATA)/$$i"; \
-		$(BIN_INSTALL) $$i $(P_DATA)/$$i; \
+		$(BIN_ECHO) "$(BIN_INSTALL) $$i $(DESTDIR)$(P_DATA)/$$i"; \
+		$(BIN_INSTALL) $$i $(DESTDIR)$(P_DATA)/$$i; \
 	done
 endif
 ifdef DATA_SHARE_DOC
-	@$(BIN_MKDIR) -p $(addprefix $(P_DOC)/, $(dir $(DATA_SHARE_DOC)))
+	@$(BIN_MKDIR) -p $(addprefix $(DESTDIR)$(P_DOC)/, $(dir $(DATA_SHARE_DOC)))
 	@for i in $(DATA_SHARE_DOC); do \
-		$(BIN_ECHO) "$(BIN_INSTALL) $$i $(P_DOC)/$$i"; \
-		$(BIN_INSTALL) $$i $(P_DOC)/$$i; \
+		$(BIN_ECHO) "$(BIN_INSTALL) $$i $(DESTDIR)$(P_DOC)/$$i"; \
+		$(BIN_INSTALL) $$i $(DESTDIR)$(P_DOC)/$$i; \
 	done
 endif
 
diff --git a/aegisub/automation/Makefile b/aegisub/automation/Makefile
index b70f8938f..e0b827525 100644
--- a/aegisub/automation/Makefile
+++ b/aegisub/automation/Makefile
@@ -35,10 +35,10 @@ all: ;
 
 
 install: install-share
-	@$(BIN_MKDIR) -p $(addprefix $(P_DATA)/automation/, $(dir $(DATA_AUTOMATION)))
+	@$(BIN_MKDIR) -p $(addprefix $(DESTDIR)$(P_DATA)/automation/, $(dir $(DATA_AUTOMATION)))
 	@for i in $(DATA_AUTOMATION); do \
-		$(BIN_ECHO) "$(BIN_INSTALL) $$i $(P_DATA)/automation/$$i"; \
-		$(BIN_INSTALL) $$i $(P_DATA)/automation/$$i; \
+		$(BIN_ECHO) "$(BIN_INSTALL) $$i $(DESTDIR)$(P_DATA)/automation/$$i"; \
+		$(BIN_INSTALL) $$i $(DESTDIR)$(P_DATA)/automation/$$i; \
 	done
 
 DATA_SHARE_DOC	= $(DATA_GENERAL_DOC) $(DATA_AUTOMATION_DOC)
diff --git a/aegisub/desktop/Makefile b/aegisub/desktop/Makefile
index d5f941ce2..559663eb9 100644
--- a/aegisub/desktop/Makefile
+++ b/aegisub/desktop/Makefile
@@ -31,19 +31,19 @@ EXTRA_DIST = \
 install: install-desktop install-icons
 
 install-desktop:
-	@$(BIN_MKDIR) -p $(P_DESKTOP)
-	$(BIN_INSTALL) $(DESKTOP_FILE) $(P_DESKTOP)/$(DESKTOP_FILE)
+	@$(BIN_MKDIR) -p $(DESTDIR)$(P_DESKTOP)
+	$(BIN_INSTALL) $(DESKTOP_FILE) $(DESTDIR)$(P_DESKTOP)/$(DESKTOP_FILE)
 
 
 install-icons:
 	@$(BIN_MKDIR) -p $(addprefix $(P_ICON)/hicolor/, $(dir $(ICON_HICOLOR)))
 	@for i in $(ICON_HICOLOR); do \
-		$(BIN_ECHO) "$(BIN_INSTALL) $$i $(P_ICON)/hicolor/$$i"; \
-		$(BIN_INSTALL) $$i $(P_ICON)/hicolor/$$i; \
+		$(BIN_ECHO) "$(BIN_INSTALL) $$i $(DESTDIR)$(P_ICON)/hicolor/$$i"; \
+		$(BIN_INSTALL) $$i $(DESTDIR)$(P_ICON)/hicolor/$$i; \
 	done
-	$(BIN_TOUCH) $(P_ICON)/hicolor
-	$(BIN_MKDIR) -p $(P_ICON)/hicolor/scalable/apps
-	$(BIN_CP) $(ICON_SCALABLE) $(P_ICON)/hicolor/$(ICON_SCALABLE)
+	$(BIN_TOUCH) $(DESTDIR)$(P_ICON)/hicolor
+	$(BIN_MKDIR) -p $(DESTDIR)$(P_ICON)/hicolor/scalable/apps
+	$(BIN_CP) $(ICON_SCALABLE) $(DESTDIR)$(P_ICON)/hicolor/$(ICON_SCALABLE)
 
 
 CLEANFILES = aegisub.desktop
diff --git a/aegisub/po/Makefile b/aegisub/po/Makefile
index bdff99ccc..3b8f4adcc 100644
--- a/aegisub/po/Makefile
+++ b/aegisub/po/Makefile
@@ -35,10 +35,10 @@ all: $(MO)
 	$(BIN_MSGFMT) -o $@ $<
 
 install:
-	@$(BIN_MKDIR) -p $(addsuffix /LC_MESSAGES/, $(addprefix $(P_LOCALE)/, $(basename $(PO))))
+	@$(BIN_MKDIR) -p $(addsuffix /LC_MESSAGES/, $(addprefix $(DESTDIR)$(P_LOCALE)/, $(basename $(PO))))
 	@for i in $(basename $(PO)); do \
-		echo $(BIN_INSTALL) $$i.mo $(P_LOCALE)/$$i/LC_MESSAGES/$(GETTEXT_PACKAGE).mo; \
-		$(BIN_INSTALL) $$i.mo $(P_LOCALE)/$$i/LC_MESSAGES/$(GETTEXT_PACKAGE).mo; \
+		echo $(BIN_INSTALL) $$i.mo $(DESTDIR)$(P_LOCALE)/$$i/LC_MESSAGES/$(GETTEXT_PACKAGE).mo; \
+		$(BIN_INSTALL) $$i.mo $(DESTDIR)$(P_LOCALE)/$$i/LC_MESSAGES/$(GETTEXT_PACKAGE).mo; \
 	done