diff --git a/src/main.c b/src/main.c
index 14b08d2..e2cc33e 100644
--- a/src/main.c
+++ b/src/main.c
@@ -3,6 +3,7 @@
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
+#define __USE_XOPEN
 #include <time.h>
 #include <unistd.h>
 #include "string.h"
@@ -66,10 +67,17 @@ static void parse_preamble(struct parser *p) {
 	int section = -1;
 	uint32_t ch;
 	char date[256];
-	time_t now;
-	time(&now);
-	struct tm *now_tm = localtime(&now);
-	strftime(date, sizeof(date), "%F", now_tm);
+	char *source_date_epoch = getenv("SOURCE_DATE_EPOCH");
+	if (source_date_epoch != NULL) {
+		struct tm source_date_epoch_tm;
+		strptime(source_date_epoch, "%s", &source_date_epoch_tm);
+		strftime(date, sizeof(date), "%F", &source_date_epoch_tm);
+	} else {
+		time_t now;
+		time(&now);
+		struct tm *now_tm = localtime(&now);
+		strftime(date, sizeof(date), "%F", now_tm);
+	}
 	while ((ch = parser_getch(p)) != UTF8_INVALID) {
 		if ((ch < 0x80 && isalnum(ch)) || ch == '_' || ch == '-' || ch == '.') {
 			assert(str_append_ch(name, ch) != -1);
diff --git a/test/preamble b/test/preamble
index 03e2d0c..eeb734b 100755
--- a/test/preamble
+++ b/test/preamble
@@ -38,31 +38,31 @@ EOF
 end 0
 
 begin "Writes the appropriate header"
-scdoc <<EOF | grep '^\.TH "test" "8" "'"$(date +'%F')"'"' >/dev/null
+scdoc <<EOF | grep '^\.TH "test" "8" "'"$(date +'%F' --date=@${SOURCE_DATE_EPOCH:-$(date +'%s')})"'"' >/dev/null
 test(8)
 EOF
 end 0
 
 begin "Preserves dashes"
-scdoc <<EOF | grep '^\.TH "test-manual" "8" "'"$(date +'%F')"'"' >/dev/null
+scdoc <<EOF | grep '^\.TH "test-manual" "8" "'"$(date +'%F' --date=@${SOURCE_DATE_EPOCH:-$(date +'%s')})"'"' >/dev/null
 test-manual(8)
 EOF
 end 0
 
 begin "Handles extra footer field"
-scdoc <<EOF | grep '^\.TH "test-manual" "8" "'"$(date +'%F')"'" "Footer"' >/dev/null
+scdoc <<EOF | grep '^\.TH "test-manual" "8" "'"$(date +'%F' --date=@${SOURCE_DATE_EPOCH:-$(date +'%s')})"'" "Footer"' >/dev/null
 test-manual(8) "Footer"
 EOF
 end 0
 
 begin "Handles both extra fields"
-scdoc <<EOF | grep '^\.TH "test-manual" "8" "'"$(date +'%F')"'" "Footer" "Header"' >/dev/null
+scdoc <<EOF | grep '^\.TH "test-manual" "8" "'"$(date +'%F' --date=@${SOURCE_DATE_EPOCH:-$(date +'%s')})"'" "Footer" "Header"' >/dev/null
 test-manual(8) "Footer" "Header"
 EOF
 end 0
 
 begin "Emits empty footer correctly"
-scdoc <<EOF | grep '^\.TH "test-manual" "8" "'"$(date +'%F')"'" "" "Header"' >/dev/null
+scdoc <<EOF | grep '^\.TH "test-manual" "8" "'"$(date +'%F' --date=@${SOURCE_DATE_EPOCH:-$(date +'%s')})"'" "" "Header"' >/dev/null
 test-manual(8) "" "Header"
 EOF
 end 0