diff --git a/modules/libcom/src/env/envDefs.h b/modules/libcom/src/env/envDefs.h
index 3bf64c861..159154b99 100644
--- a/modules/libcom/src/env/envDefs.h
+++ b/modules/libcom/src/env/envDefs.h
@@ -76,6 +76,7 @@ LIBCOM_API extern const ENV_PARAM EPICS_IOC_LOG_FILE_COMMAND;
 LIBCOM_API extern const ENV_PARAM IOCSH_PS1;
 LIBCOM_API extern const ENV_PARAM IOCSH_HISTSIZE;
 LIBCOM_API extern const ENV_PARAM IOCSH_HISTEDIT_DISABLE;
+LIBCOM_API extern const ENV_PARAM EPICS_MUTEX_USE_PRIORITY_INHERITANCE;
 LIBCOM_API extern const ENV_PARAM *env_param_list[];
 
 struct in_addr;
diff --git a/modules/libcom/src/osi/os/posix/osdMutex.c b/modules/libcom/src/osi/os/posix/osdMutex.c
index 33a9594ce..401f59395 100644
--- a/modules/libcom/src/osi/os/posix/osdMutex.c
+++ b/modules/libcom/src/osi/os/posix/osdMutex.c
@@ -23,6 +23,7 @@
 #include <errno.h>
 #include <unistd.h>
 #include <pthread.h>
+#include <ctype.h>
 
 #define EPICS_PRIVATE_API
 
@@ -34,6 +35,7 @@
 #include "errlog.h"
 #include "epicsStdio.h"
 #include "epicsAssert.h"
+#include "envDefs.h"
 
 #define checkStatus(status,message) \
     if((status)) { \
@@ -69,21 +71,27 @@ static void globalAttrInit()
     status = pthread_mutexattr_settype(&globalAttrRecursive, PTHREAD_MUTEX_RECURSIVE);
     checkStatusQuit(status, "pthread_mutexattr_settype(&globalAttrRecursive, PTHREAD_MUTEX_RECURSIVE)", "globalAttrInit");
 #if defined _POSIX_THREAD_PRIO_INHERIT
-    status = pthread_mutexattr_setprotocol(&globalAttrDefault, PTHREAD_PRIO_INHERIT);
-    if (errVerbose) checkStatus(status, "pthread_mutexattr_setprotocol(&globalAttrDefault, PTHREAD_PRIO_INHERIT)");
-    status = pthread_mutexattr_setprotocol(&globalAttrRecursive, PTHREAD_PRIO_INHERIT);
-    if (errVerbose) checkStatus(status, "pthread_mutexattr_setprotocol(&globalAttrRecursive, PTHREAD_PRIO_INHERIT)");
-    if (status == 0) {
-        /* Can we really use PTHREAD_PRIO_INHERIT? */
-        pthread_mutex_t temp;
-        status = pthread_mutex_init(&temp, &globalAttrRecursive);
-        if (errVerbose) checkStatus(status, "pthread_mutex_init(&temp, &globalAttrRecursive)");
-        if (status != 0) {
-            /* No, PTHREAD_PRIO_INHERIT does not work, fall back to PTHREAD_PRIO_NONE */;
-            pthread_mutexattr_setprotocol(&globalAttrDefault, PTHREAD_PRIO_NONE);
-            pthread_mutexattr_setprotocol(&globalAttrRecursive, PTHREAD_PRIO_NONE);
-        } else {
-            pthread_mutex_destroy(&temp);
+    {
+        const char *p = envGetConfigParamPtr(&EPICS_MUTEX_USE_PRIORITY_INHERITANCE);
+        char c = p ? toupper(p[0]) : 'N';
+        if ( 'T' == c || 'Y' == c || '1' == c ) {
+            status = pthread_mutexattr_setprotocol(&globalAttrDefault, PTHREAD_PRIO_INHERIT);
+            if (errVerbose) checkStatus(status, "pthread_mutexattr_setprotocol(&globalAttrDefault, PTHREAD_PRIO_INHERIT)");
+            status = pthread_mutexattr_setprotocol(&globalAttrRecursive, PTHREAD_PRIO_INHERIT);
+            if (errVerbose) checkStatus(status, "pthread_mutexattr_setprotocol(&globalAttrRecursive, PTHREAD_PRIO_INHERIT)");
+            if (status == 0) {
+                /* Can we really use PTHREAD_PRIO_INHERIT? */
+                pthread_mutex_t temp;
+                status = pthread_mutex_init(&temp, &globalAttrRecursive);
+                if (errVerbose) checkStatus(status, "pthread_mutex_init(&temp, &globalAttrRecursive)");
+                if (status != 0) {
+                    /* No, PTHREAD_PRIO_INHERIT does not work, fall back to PTHREAD_PRIO_NONE */;
+                    pthread_mutexattr_setprotocol(&globalAttrDefault, PTHREAD_PRIO_NONE);
+                    pthread_mutexattr_setprotocol(&globalAttrRecursive, PTHREAD_PRIO_NONE);
+                } else {
+                    pthread_mutex_destroy(&temp);
+                }
+            }
         }
     }
 #endif