diff --git a/docs/querying/basics.md b/docs/querying/basics.md
index 062e2fe203..65798b74fe 100644
--- a/docs/querying/basics.md
+++ b/docs/querying/basics.md
@@ -116,6 +116,9 @@ The following expression selects all metrics that have a name starting with `job
 
     {__name__=~"job:.*"}
 
+All regular expressions in Prometheus use [RE2
+syntax](https://github.com/google/re2/wiki/Syntax).
+
 ### Range Vector Selectors
 
 Range vector literals work like instant vector literals, except that they
diff --git a/docs/querying/examples.md b/docs/querying/examples.md
index 589d6bbca6..5827ca5eb7 100644
--- a/docs/querying/examples.md
+++ b/docs/querying/examples.md
@@ -31,6 +31,9 @@ Note that this does a substring match, not a full string match:
 
     http_requests_total{job=~".*server"}
 
+All regular expressions in Prometheus use [RE2
+syntax](https://github.com/google/re2/wiki/Syntax).
+
 To select all HTTP status codes except 4xx ones, you could run:
 
     http_requests_total{status!~"4.."}