diff --git a/brush-core/src/builtins/unset.rs b/brush-core/src/builtins/unset.rs
index 94ac0052..da3b1c67 100644
--- a/brush-core/src/builtins/unset.rs
+++ b/brush-core/src/builtins/unset.rs
@@ -60,11 +60,14 @@ impl builtins::Command for UnsetCommand {
                         context.shell.env.unset(name.as_str())?
                     }
                     brush_parser::word::Parameter::NamedWithIndex { name, index } => {
-                        // TODO: Evaluate index?
+                        // First evaluate the index expression.
+                        let index_as_expr = brush_parser::arithmetic::parse(index.as_str())?;
+                        let evaluated_index = context.shell.eval_arithmetic(index_as_expr).await?;
+
                         context
                             .shell
                             .env
-                            .unset_index(name.as_str(), index.as_str())?
+                            .unset_index(name.as_str(), evaluated_index.to_string().as_str())?
                     }
                     brush_parser::word::Parameter::NamedWithAllIndices {
                         name: _,
diff --git a/brush-parser/src/word.rs b/brush-parser/src/word.rs
index bb965db1..f426e9fb 100644
--- a/brush-parser/src/word.rs
+++ b/brush-parser/src/word.rs
@@ -653,7 +653,7 @@ peg::parser! {
             p:special_parameter() { Parameter::Special(p) } /
             non_posix_extensions_enabled() p:variable_name() "[@]" { Parameter::NamedWithAllIndices { name: p.to_owned(), concatenate: false } } /
             non_posix_extensions_enabled() p:variable_name() "[*]" { Parameter::NamedWithAllIndices { name: p.to_owned(), concatenate: true } } /
-            non_posix_extensions_enabled() p:variable_name() "[" index:$((!"]" [_])*) "]" {?
+            non_posix_extensions_enabled() p:variable_name() "[" index:$(arithmetic_word(<"]">)) "]" {?
                 Ok(Parameter::NamedWithIndex { name: p.to_owned(), index: index.to_owned() })
             } /
             p:variable_name() { Parameter::Named(p.to_owned()) }
diff --git a/brush-shell/tests/cases/arrays.yaml b/brush-shell/tests/cases/arrays.yaml
index 21abb97d..b548d35f 100644
--- a/brush-shell/tests/cases/arrays.yaml
+++ b/brush-shell/tests/cases/arrays.yaml
@@ -270,3 +270,8 @@ cases:
     stdin: |
       declare -A myarray=([0]="default" ["a"]="other")
       echo "Value: ${myarray[$non_existent_var]}"
+
+  - name: "Nested array reference"
+    stdin: |
+      x=(2 3 4)
+      echo ${x[${x[0]}]}
diff --git a/brush-shell/tests/cases/builtins/unset.yaml b/brush-shell/tests/cases/builtins/unset.yaml
index 1081c20a..dfbae9fd 100644
--- a/brush-shell/tests/cases/builtins/unset.yaml
+++ b/brush-shell/tests/cases/builtins/unset.yaml
@@ -48,12 +48,23 @@ cases:
       declare -p myarray
 
   - name: "Unset array element with interesting expression"
-    known_failure: true # TODO: case needs implementing
     stdin: |
       declare -a myarray=(a b c d e)
 
+      echo "Initial array:"
+      declare -p myarray
+      echo
+
+      i=4
+      unset myarray[i]
+      echo "After removing element at index 4:"
+      declare -p myarray
+      echo
+
       unset myarray[6/2]
+      echo "After removing element at index 3:"
       declare -p myarray
+      echo
 
   - name: "Unset local in same function"
     stdin: |