diff --git a/src/proto/alpha/docs/language.md b/src/proto/alpha/docs/language.md
index 3750dd8ed..b75af370e 100644
--- a/src/proto/alpha/docs/language.md
+++ b/src/proto/alpha/docs/language.md
@@ -471,6 +471,11 @@ IV - Core instructions
 
         > UNIT / S   =>   Unit : S
 
+   * `LAMBDA 'a 'b code`:
+     Push a lambda with given parameter and return types onto the stack.
+
+        :: 'A ->  (lambda 'a 'b) : 'A
+
 ### Generic comparison
 
 Comparison only works on a class of types that we call comparable.