diff --git a/src/USER-MISC/pair_nb3b_harmonic.cpp b/src/USER-MISC/pair_nb3b_harmonic.cpp
index 39dce42468..d5b48b26b1 100644
--- a/src/USER-MISC/pair_nb3b_harmonic.cpp
+++ b/src/USER-MISC/pair_nb3b_harmonic.cpp
@@ -45,6 +45,7 @@ PairNb3bHarmonic::PairNb3bHarmonic(LAMMPS *lmp) : Pair(lmp)
 {
   single_enable = 0;
   one_coeff = 1;
+  manybody_flag = 1;
 
   nelements = 0;
   elements = NULL;