diff --git a/diophantine_classifier/data/families/prouhet-tarry-escott.yaml b/diophantine_classifier/data/families/prouhet-tarry-escott.yaml
new file mode 100644
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+++ b/diophantine_classifier/data/families/prouhet-tarry-escott.yaml
@@ -0,0 +1,15 @@
+# Family: Prouhet-Tarry-Escott problem
+# Schema: see data/families/README.md; prose documentation in docs/FAMILIES.md.
+# References are keys into data/references.bib, each with a 'why' annotation.
+slug: prouhet-tarry-escott
+name: Prouhet-Tarry-Escott problem
+priority: 3
+status: open
+class: surface
+form: sum x_i^j = sum y_i^j for j = 1..k
+parents:
+- equal-sums-like-powers
+matcher: false
+references:
+- key: BorweinIngalls1994
+  why: survey of ideal solutions and open problems
diff --git a/docs/FAMILIES.md b/docs/FAMILIES.md
index 86434cf..e801ea8 100644
--- a/docs/FAMILIES.md
+++ b/docs/FAMILIES.md
@@ -310,6 +310,12 @@ the multi-degree system version.
 **References.** Lander–Parkin 1966; Elkies 1988; Borwein, *Computational Excursions
 in Analysis and Number Theory* (PTE chapters).
 
+### `prouhet-tarry-escott` — Prouhet–Tarry–Escott — P3, open
+**Form.** Σ x_i^j = Σ y_i^j for j = 1,…,k simultaneously (ideal: size k+1).
+**Status.** Ideal solutions known only in scattered sizes; existence in all sizes
+open; deep links to combinatorics and analysis.
+**References.** Borwein–Ingalls, "The Prouhet–Tarry–Escott problem revisited" (1994).
+
 
 ---