diff --git a/bin/mpirunDebug b/bin/mpirunDebug
index 695c0fae5e..b4fcb976e7 100755
--- a/bin/mpirunDebug
+++ b/bin/mpirunDebug
@@ -429,7 +429,7 @@ unset cmd
 
 case "$WM_MPLIB" in
 *OPENMPI*)
-    cmd="mpirun -app $PWD/mpirun.schema </dev/null"
+    cmd="mpirun --oversubscribe -app $PWD/mpirun.schema </dev/null"
     ;;
 MPICH)
     cmd="mpiexec"
diff --git a/bin/tools/RunFunctions b/bin/tools/RunFunctions
index f8482f63f2..03bd194919 100644
--- a/bin/tools/RunFunctions
+++ b/bin/tools/RunFunctions
@@ -304,16 +304,21 @@ runApplication()
 #
 runParallel()
 {
-    local appName appRun optValue logFile logMode nProcs
+    local appName appRun optValue logFile logMode
+    local mpiopts nProcs
 
     # Any additional parsed arguments (eg, decomposeParDict)
     local appArgs="-parallel"
 
     local mpirun="mpirun"
-    if [ "$FOAM_MPI" = msmpi ]
-    then
+    case "$FOAM_MPI" in
+    (msmpi*)
         mpirun="mpiexec"
-    fi
+        ;;
+    (*openmpi*)
+        mpiopts="--oversubscribe"
+        ;;
+    esac
 
     # Parse options until executable is encountered
     while [ "$#" -gt 0 ] && [ -z "$appRun" ]
@@ -378,11 +383,11 @@ runParallel()
         if [ "$logMode" = append ]
         then
         (
-            $mpirun -n $nProcs $appRun $appArgs "$@" </dev/null >> $logFile 2>&1
+            "$mpirun" $mpiopts -n "${nProcs:?}" $appRun $appArgs "$@" </dev/null >> $logFile 2>&1
         )
         else
         (
-            $mpirun -n $nProcs $appRun $appArgs "$@" </dev/null > $logFile 2>&1
+            "$mpirun" $mpiopts -n "${nProcs:?}" $appRun $appArgs "$@" </dev/null > $logFile 2>&1
         )
         fi
     fi