diff --git a/core/platform.h b/core/platform.h
index 8453cf25e..14a67c2a2 100644
--- a/core/platform.h
+++ b/core/platform.h
@@ -90,6 +90,11 @@ typedef _microstep_t microstep_t;
 
 #ifdef NUMBER_OF_WORKERS
 
+/**
+ * @brief Get the number of cores on the host machine.
+ */
+extern int lf_available_cores();
+
 /**
  * Create a new thread, starting with execution of lf_thread
  * getting passed arguments. The new handle is stored in thread_id.
diff --git a/core/platform/lf_linux_support.c b/core/platform/lf_linux_support.c
index b7a87d72c..58188f022 100644
--- a/core/platform/lf_linux_support.c
+++ b/core/platform/lf_linux_support.c
@@ -41,6 +41,7 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #endif
 
 #include "lf_unix_clock_support.c"
+#include "lf_unix_syscall_support.c"
 
 /**
  * Pause execution for a number of nanoseconds.
diff --git a/core/platform/lf_macos_support.c b/core/platform/lf_macos_support.c
index 5344d03e1..c0836d02e 100644
--- a/core/platform/lf_macos_support.c
+++ b/core/platform/lf_macos_support.c
@@ -41,6 +41,7 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #endif
 
 #include "lf_unix_clock_support.c"
+#include "lf_unix_syscall_support.c"
 
 /**
  * Pause execution for a number of nanoseconds.
diff --git a/core/platform/lf_unix_syscall_support.c b/core/platform/lf_unix_syscall_support.c
new file mode 100644
index 000000000..e3cacc3ca
--- /dev/null
+++ b/core/platform/lf_unix_syscall_support.c
@@ -0,0 +1,19 @@
+/**
+ * @file lf_unix_syscall_support.c
+ * @author Soroush Bateni (soroush@utdallas.edu)
+ * @brief Platform support for syscalls in Unix-like systems.
+ * @version 0.1
+ * @date 2022-03-09
+ * 
+ * @copyright Copyright (c) 2022 The University of Texas at Dallas
+ * 
+ */
+
+#include <unistd.h>
+
+/**
+ * @brief Get the number of cores on the host machine.
+ */
+int lf_available_cores() {
+    return (int)sysconf(_SC_NPROCESSORS_ONLN);
+}
diff --git a/core/platform/lf_windows_support.c b/core/platform/lf_windows_support.c
index f5f3438e7..a09d5880a 100644
--- a/core/platform/lf_windows_support.c
+++ b/core/platform/lf_windows_support.c
@@ -35,6 +35,7 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <windows.h>
 #include <process.h>
+#include <sysinfoapi.h>
 #include <errno.h>
 #include "lf_windows_support.h"
 #include "../platform.h"
@@ -56,6 +57,15 @@ double _lf_frequency_to_ns = 1.0;
 #define BILLION 1000000000
 
 #ifdef NUMBER_OF_WORKERS
+/**
+ * @brief Get the number of cores on the host machine.
+ */
+int lf_available_cores() {
+    SYSTEM_INFO sysinfo;
+    GetSystemInfo(&sysinfo);
+    return sysinfo.dwNumberOfProcessors;
+}
+
 #if __STDC_VERSION__ < 201112L || defined (__STDC_NO_THREADS__) // (Not C++11 or later) or no threads support
 
 /**
diff --git a/core/reactor.h b/core/reactor.h
index 0bc0f05a3..607be8a59 100644
--- a/core/reactor.h
+++ b/core/reactor.h
@@ -943,7 +943,7 @@ bool _lf_check_deadline(self_base_t* self, bool invoke_deadline_handler);
  * By default, execution is not threaded and this variable will have value 0,
  * meaning that the execution is not threaded.
  */
-extern unsigned int _lf_number_of_threads;
+extern unsigned int _lf_number_of_workers;
 
 #include "trace.h"
 
diff --git a/core/reactor_common.c b/core/reactor_common.c
index 32fa3006e..1b20ffeda 100644
--- a/core/reactor_common.c
+++ b/core/reactor_common.c
@@ -49,10 +49,13 @@ bool fast = false;
 
 /**
  * The number of worker threads for threaded execution.
- * By default, execution is not threaded and this variable will have value 0,
- * meaning that the execution is not threaded.
+ * By default, execution is not threaded and this variable will have value 0.
+ * 
+ * If the execution is threaded, a value of 0 indicates that the runtime should
+ * decide on the number of workers (which will be decided based on the number of
+ * available cores on the host machine).
  */
-unsigned int _lf_number_of_threads = 0u;
+unsigned int _lf_number_of_workers = 0u;
 
 /** 
  * The logical time to elapse during execution, or -1 if no timeout time has
@@ -1719,7 +1722,7 @@ void usage(int argc, char* argv[]) {
     printf("   nsec, usec, msec, sec, minute, hour, day, week, or the plurals of those.\n\n");
     printf("  -k, --keepalive\n");
     printf("   Whether continue execution even when there are no events to process.\n\n");
-    printf("  -t, --threads <n>\n");
+    printf("  -w, --workers <n>\n");
     printf("   Executed in <n> threads if possible (optional feature).\n\n");
     printf("  -i, --id <n>\n");
     printf("   The ID of the federation that this reactor will join.\n\n");
@@ -1819,19 +1822,19 @@ int process_args(int argc, char* argv[]) {
             } else {
                 error_print("Invalid value for --keepalive: %s", keep_spec);
             }
-        } else if (strcmp(arg, "-t") == 0 || strcmp(arg, "--threads") == 0) {
+        } else if (strcmp(arg, "-t") == 0 || strcmp(arg, "--workers") == 0) {
             if (argc < i + 1) {
-                error_print("--threads needs an integer argument.s");
+                error_print("--workers needs an integer argument.s");
                 usage(argc, argv);
                 return 0;
             }
             char* threads_spec = argv[i++];
-            int num_threads = atoi(threads_spec);
-            if (num_threads <= 0) {
-                error_print("Invalid value for --threads: %s. Using 1.", threads_spec);
-                num_threads = 1;
+            int num_workers = atoi(threads_spec);
+            if (num_workers <= 0) {
+                error_print("Invalid value for --workers: %s. Using 1.", threads_spec);
+                num_workers = 1;
             }
-            _lf_number_of_threads = (unsigned int)num_threads;
+            _lf_number_of_workers = (unsigned int)num_workers;
         }
         #ifdef FEDERATED
           else if (strcmp(arg, "-i") == 0 || strcmp(arg, "--id") == 0) {
diff --git a/core/threaded/reactor_threaded.c b/core/threaded/reactor_threaded.c
index 66227a92e..c3b7bc2c2 100644
--- a/core/threaded/reactor_threaded.c
+++ b/core/threaded/reactor_threaded.c
@@ -1080,13 +1080,37 @@ lf_thread_t* _lf_thread_ids;
 
 // Start threads in the thread pool.
 void start_threads() {
-    LOG_PRINT("Starting %u worker threads.", _lf_number_of_threads);
-    _lf_thread_ids = (lf_thread_t*)malloc(_lf_number_of_threads * sizeof(lf_thread_t));
-    for (unsigned int i = 0; i < _lf_number_of_threads; i++) {
+    LOG_PRINT("Starting %u worker threads.", _lf_number_of_workers);
+    _lf_thread_ids = (lf_thread_t*)malloc(_lf_number_of_workers * sizeof(lf_thread_t));
+    for (unsigned int i = 0; i < _lf_number_of_workers; i++) {
         lf_thread_create(&_lf_thread_ids[i], worker, NULL);
     }
 }
 
+/**
+ * @brief Determine the number of workers.
+ * 
+ */
+void determine_number_of_workers(void) {
+    // If _lf_number_of_workers is 0, it means that it was not provided on
+    // the command-line using the --threads argument.
+    if (_lf_number_of_workers == 0u) {
+        #if !defined(NUMBER_OF_WORKERS) || NUMBER_OF_WORKERS == 0
+        // Use the number of cores on the host machine.
+        _lf_number_of_workers = lf_available_cores();
+        #else
+        // Use the provided number of workers by the user
+        _lf_number_of_workers = NUMBER_OF_WORKERS;
+        #endif
+    }
+
+    #if defined(WORKERS_NEEDED_FOR_FEDERATE)
+    // Add the required number of workers needed for the proper function of
+    // federated execution
+    _lf_number_of_workers += WORKERS_NEEDED_FOR_FEDERATE;
+    #endif
+}
+
 /**
  * The main loop of the LF program.
  * 
@@ -1137,12 +1161,17 @@ int lf_reactor_c_main(int argc, char* argv[]) {
 
     if (process_args(default_argc, default_argv)
             && process_args(argc, argv)) {
-        lf_mutex_lock(&mutex); // Sets start_time
-        initialize();
+        
+        determine_number_of_workers();
+
+        lf_mutex_lock(&mutex);
+        initialize(); // Sets start_time
+
+        info_print("---- Using %d workers.", _lf_number_of_workers);
         
         // Initialize the scheduler
         lf_sched_init(
-            (size_t)_lf_number_of_threads, 
+            (size_t)_lf_number_of_workers, 
             NULL);
 
         // Call the following function only once, rather than per worker thread (although 
@@ -1156,9 +1185,9 @@ int lf_reactor_c_main(int argc, char* argv[]) {
 
         // Wait for the worker threads to exit.
         void* worker_thread_exit_status = NULL;
-        DEBUG_PRINT("Number of threads: %d.", _lf_number_of_threads);
+        DEBUG_PRINT("Number of threads: %d.", _lf_number_of_workers);
         int ret = 0;
-        for (int i = 0; i < _lf_number_of_threads; i++) {
+        for (int i = 0; i < _lf_number_of_workers; i++) {
         	int failure = lf_thread_join(_lf_thread_ids[i], &worker_thread_exit_status);
         	if (failure) {
         		error_print("Failed to join thread listening for incoming messages: %s", strerror(failure));
diff --git a/core/trace.c b/core/trace.c
index aa7c88721..379b0d6a8 100644
--- a/core/trace.c
+++ b/core/trace.c
@@ -329,7 +329,7 @@ void start_trace(char* filename) {
     // Allocate an array of arrays of trace records, one per worker thread plus one
     // for the 0 thread (the main thread, or in an unthreaded program, the only
     // thread).
-    _lf_number_of_trace_buffers = _lf_number_of_threads + 1;
+    _lf_number_of_trace_buffers = _lf_number_of_workers + 1;
     _lf_trace_buffer = (trace_record_t**)malloc(sizeof(trace_record_t*) * _lf_number_of_trace_buffers);
     for (int i = 0; i < _lf_number_of_trace_buffers; i++) {
         _lf_trace_buffer[i] = (trace_record_t*)malloc(sizeof(trace_record_t) * TRACE_BUFFER_CAPACITY);
diff --git a/lingua-franca-ref.txt b/lingua-franca-ref.txt
index 040b9b95d..16d32048d 100644
--- a/lingua-franca-ref.txt
+++ b/lingua-franca-ref.txt
@@ -1 +1 @@
-14e26feddb2e2770596c22b2e9a2397c53d468dd
+276cb2592c20cc6da2f5722dc013581b085e5d4c