diff --git a/README.md b/README.md
index 8116c1a15b61943a17c52de81c56640386ad530b..f5f29aa35614327c5eb480837235273136573dc9 100644
--- a/README.md
+++ b/README.md
@@ -241,6 +241,13 @@ Versatile MCMC phylogeny building using Python.
 
 URL: <https://p4.nhm.ac.uk/>
 
+### tskit
+
+URL: <https://tskit.dev/genetics-research/>
+
+To work with "succint tree sequences", an efficient genomic data storage format
+supposedly useful for population genetics and phylogeny. I haven't used it yet.
+
 
 ## Not a library