diff --git a/doc/man.md.j2 b/doc/man.md.j2
index 85d1eda483..bd9db7fb88 100644
--- a/doc/man.md.j2
+++ b/doc/man.md.j2
@@ -163,7 +163,7 @@ file.
 **-U \| \--unique**
 
 :   Conky won't start if another Conky process is already running. Implemented
-    only for Linux and FreeBSD.
+    only for Linux, FreeBSD and Haiku.
 
 **-v \| -V \| \--version** 
 
diff --git a/src/common.cc b/src/common.cc
index 4b63b9dd5a..ae4e26b32c 100644
--- a/src/common.cc
+++ b/src/common.cc
@@ -56,7 +56,7 @@
 #include "timeinfo.h"
 #include "top.h"
 
-#if defined(_POSIX_C_SOURCE) && !defined(__OpenBSD__)
+#if defined(_POSIX_C_SOURCE) && !defined(__OpenBSD__) && !defined(__HAIKU__)
 #include <wordexp.h>
 #endif
 
@@ -141,7 +141,7 @@ double get_time() {
   return tv.tv_sec + (tv.tv_nsec * 1e-9);
 }
 
-#if defined(_POSIX_C_SOURCE) && !defined(__OpenBSD__)
+#if defined(_POSIX_C_SOURCE) && !defined(__OpenBSD__) && !defined(__HAIKU__)
 std::filesystem::path to_real_path(const std::string &source) {
   wordexp_t p;
   char **w;
diff --git a/src/conky.cc b/src/conky.cc
index 3589d568c5..c450365c6d 100644
--- a/src/conky.cc
+++ b/src/conky.cc
@@ -2109,9 +2109,10 @@ void set_current_config() {
 /* : means that character before that takes an argument */
 const char *getopt_string =
     "vVqdDSs:t:u:i:hc:p:"
-#if defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+#if defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || \
+    defined(__HAIKU__)
     "U"
-#endif /* Linux || FreeBSD */
+#endif /* Linux || FreeBSD || Haiku */
 #ifdef BUILD_X11
     "x:y:w:a:X:m:f:"
 #ifdef OWN_WINDOW
@@ -2142,9 +2143,10 @@ const struct option longopts[] = {
 #endif /* BUILD_X11 */
     {"text", 1, nullptr, 't'},          {"interval", 1, nullptr, 'u'},
     {"pause", 1, nullptr, 'p'},
-#if defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+#if defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || \
+    defined(__HAIKU__)
     {"unique", 0, nullptr, 'U'},
-#endif /* Linux || FreeBSD */
+#endif /* Linux || FreeBSDi || Haiku */
     {nullptr, 0, nullptr, 0}
 };
 
diff --git a/src/haiku.cc b/src/haiku.cc
index 73ec54f78c..7029df1927 100644
--- a/src/haiku.cc
+++ b/src/haiku.cc
@@ -247,3 +247,25 @@ void get_battery_short_status(char *buffer, unsigned int n, const char *bat) {
 int get_entropy_avail(unsigned int *val) { return 1; }
 
 int get_entropy_poolsize(unsigned int *val) { return 1; }
+
+/******************************************
+ * Check if more than one conky process   *
+ * is running                             *
+ ******************************************/
+
+bool is_conky_already_running(void) {
+  int32 team_cookie = 0;
+  team_info team_info;
+  int32 thread_cookie = 0;
+  thread_info thread_info;
+  int32 instances = 0;
+
+  while (get_next_team_info(&team_cookie, &team_info) >= B_OK) {
+    while (get_next_thread_info(team_info.team, &thread_cookie, &thread_info) >= B_OK) {
+      if (!strcmp("conky", thread_info.name)) {
+        ++instances;
+      }
+    }
+  }
+  return instances > 1;
+}
diff --git a/src/haiku.h b/src/haiku.h
index 801000b9f3..84c93208c6 100644
--- a/src/haiku.h
+++ b/src/haiku.h
@@ -18,6 +18,8 @@
 
 #include <kernel/fs_info.h>
 
+#include <OS.h>
+
 #include "common.h"
 #include "conky.h"
 
@@ -38,4 +40,6 @@ inline int statfs(const char *path, struct statfs *buf) {
 #define f_bfree free_blocks
 #define f_fstypename fsh_name
 
+bool is_conky_already_running(void);
+
 #endif /*HAIKU_H_*/
diff --git a/src/main.cc b/src/main.cc
index 1b561681ae..2b0bf4e6eb 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -52,6 +52,10 @@
 #include "freebsd.h"
 #endif /* FreeBSD */
 
+#if defined(__HAIKU__)
+#include "haiku.h"
+#endif /* Haiku */
+
 #ifdef BUILD_BUILTIN_CONFIG
 #include "defconfig.h"
 
@@ -273,9 +277,10 @@ static void print_help(const char *prog_name) {
          " (and quit)\n"
          "   -p, --pause=SECS          pause for SECS seconds at startup "
          "before doing anything\n"
-#if defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+#if defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || \
+    defined(__HAIKU__)
          "   -U, --unique              only one conky process can be created\n"
-#endif /* Linux || FreeBSD */
+#endif /* Linux || FreeBSD || Haiku */
          , prog_name);
 }
 
@@ -358,22 +363,24 @@ int main(int argc, char **argv) {
         window.window = strtol(optarg, nullptr, 0);
         break;
 #endif /* BUILD_X11 */
-#if defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+#if defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || \
+    defined(__HAIKU__)
       case 'U':
         unique_process = true;
         break;
-#endif /* Linux || FreeBSD */
+#endif /* Linux || FreeBSD || Haiku */
       case '?':
         return EXIT_FAILURE;
     }
   }
 
-#if defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+#if defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || \
+    defined(__HAIKU__)
   if (unique_process && is_conky_already_running()) {
     NORM_ERR("already running");
     return 0;
   }
-#endif /* Linux || FreeBSD */
+#endif /* Linux || FreeBSD || Haiku */
 
   try {
     set_current_config();