diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index d75ca0be..b3de84e7 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -1036,6 +1036,7 @@ void DerivationGoal::killChild()
                it won't be killed, and we'll potentially lock up in
                pid.wait().  So also send a conventional kill to the
                child. */
+            ::kill(-pid, SIGTERM); /* ignore the result */
             ::kill(-pid, SIGKILL); /* ignore the result */
             buildUser->kill();
             pid.wait();
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 6bc64ae7..7ff4de24 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -779,7 +779,7 @@ void Pid::operator =(pid_t pid)
 {
     if (this->pid != -1 && this->pid != pid) kill();
     this->pid = pid;
-    killSignal = SIGKILL; // reset signal to default
+    killSignal = SIGTERM; // reset signal to default
 }
 
 
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index fc25d277..2e0d98f8 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -218,7 +218,7 @@ class Pid
 {
     pid_t pid = -1;
     bool separatePG = false;
-    int killSignal = SIGKILL;
+    int killSignal = SIGTERM;
 public:
     Pid();
     Pid(pid_t pid);