diff --git a/main.c b/main.c
index 823401e..b72e11c 100644
--- a/main.c
+++ b/main.c
@@ -10,6 +10,14 @@
 #include <time.h>
 #include <unistd.h>
 
+#ifdef __OpenBSD__
+#define SIG_MIN SIGUSR1
+#define SIG_MAX 31
+#else
+#define SIG_MIN SIGRTMIN
+#define SIG_MAX SIGRTMAX
+#endif
+
 #ifdef HAS_X11
 #include <X11/Xlib.h>
 #endif
@@ -526,10 +534,10 @@ static void initialize_modules() {
         if (modules[i].disabled) {
             continue;
         }
-        if (modules[i].signal + SIGRTMIN > SIGRTMAX) {
+        if (modules[i].signal + SIG_MIN > SIG_MAX) {
             has_error = TRUE;
             qtb_log("%s: error: signal out of range: %d\n",
-                    modules[i].signal + SIGRTMIN);
+                    modules[i].signal + SIG_MIN);
             continue;
         }
         if (modules[i].init) {
@@ -561,7 +569,7 @@ static void signal_handler(int signum) {
     clock_gettime(global_cpu_clock_id, &current_time);
     int module_updated = FALSE;
     unsigned long current_time_ms = timespec_to_miliseconds(&current_time);
-    int adjusted_signum = signum - SIGRTMIN;
+    int adjusted_signum = signum - SIG_MIN;
     size_t i;
     for (i = 0; i < global_module_count; ++i) {
         if (!modules[i].disabled && modules[i].signal == adjusted_signum) {
@@ -578,7 +586,7 @@ static void signal_handler(int signum) {
 static void setup_signals() {
     sigemptyset(&global_real_time_mask);
     int i;
-    for (i = SIGRTMIN; i <= SIGRTMAX; ++i) {
+    for (i = SIG_MIN; i <= SIG_MAX; ++i) {
         sigaddset(&global_real_time_mask, i);
         struct sigaction action;
         sigemptyset(&action.sa_mask);
@@ -788,7 +796,7 @@ void qtb_die() {
 }
 
 void qtb_signal_modules(int sig) {
-    pthread_kill(global_main_thread, SIGRTMIN + sig);
+    pthread_kill(global_main_thread, SIG_MIN + sig);
 }
 
 void *qtb_malloc(size_t size) {