diff --git a/python/lsst/meas/algorithms/gp_interpolation.py b/python/lsst/meas/algorithms/gp_interpolation.py
index 21d799c8..2c343cbf 100644
--- a/python/lsst/meas/algorithms/gp_interpolation.py
+++ b/python/lsst/meas/algorithms/gp_interpolation.py
@@ -24,10 +24,15 @@
 from lsst.geom import Box2I, Point2I
 from lsst.afw.geom import SpanSet
 import copy
+import treecorr
 import treegp
 
 import logging
 
+# We need to explicitly turn off multiprocessing in treecorr which is used
+# by treegp.
+treecorr.set_max_omp_threads(1)
+
 __all__ = [
     "InterpolateOverDefectGaussianProcess",
     "GaussianProcessTreegp",