diff --git a/src/expand.cpp b/src/expand.cpp
index fbdc8c8d0..5f0b362c6 100644
--- a/src/expand.cpp
+++ b/src/expand.cpp
@@ -1211,7 +1211,9 @@ std::map<wcstring, wcstring> get_abbreviations(const environment_t &vars) {
     std::map<wcstring, wcstring> result;
     for (const wcstring &name : names) {
         if (string_prefixes_string(prefix, name)) {
-            result[name.substr(prefix.size())] = vars.get(name)->as_string();
+            wcstring key;
+            unescape_string(name.substr(prefix.size()), &key, UNESCAPE_DEFAULT, STRING_STYLE_VAR);
+            result[key] = vars.get(name)->as_string();
         }
     }
     return result;
diff --git a/src/expand.h b/src/expand.h
index 371724307..3737d8494 100644
--- a/src/expand.h
+++ b/src/expand.h
@@ -177,6 +177,7 @@ wcstring replace_home_directory_with_tilde(const wcstring &str, const environmen
 maybe_t<wcstring> expand_abbreviation(const wcstring &src, const environment_t &vars);
 
 /// \return a snapshot of all abbreviations as a map abbreviation->expansion.
+/// The abbreviations are unescaped, i.e. they may not be valid variable identifiers (#6166).
 std::map<wcstring, wcstring> get_abbreviations(const environment_t &vars);
 
 // Terrible hacks
diff --git a/tests/checks/abbr.fish b/tests/checks/abbr.fish
index dd8eaddd3..b2c3a64ef 100644
--- a/tests/checks/abbr.fish
+++ b/tests/checks/abbr.fish
@@ -85,3 +85,7 @@ abbr __abbr11 omega11
 abbr __abbr12 omega12
 abbr -r __abbr11 __abbr12
 # CHECKERR: abbr --rename: Abbreviation __abbr12 already exists, cannot rename __abbr11
+
+abbr __abbr-with-dashes omega
+complete -C__abbr-with
+# CHECK: __abbr-with-dashes	Abbreviation: omega