diff --git a/ql/src/codeql_ruby/ast/Variable.qll b/ql/src/codeql_ruby/ast/Variable.qll
index 73b4e2a0593..06dee5ef89b 100644
--- a/ql/src/codeql_ruby/ast/Variable.qll
+++ b/ql/src/codeql_ruby/ast/Variable.qll
@@ -53,30 +53,47 @@ class Variable extends TVariable {
 }
 
 /** A local variable. */
-class LocalVariable extends Variable {
+class LocalVariable extends Variable, TLocalVariable {
   override LocalVariable::Range range;
 
   final override LocalVariableAccess getAnAccess() { result.getVariable() = this }
 }
 
+/** A global variable. */
+class GlobalVariable extends Variable, TGlobalVariable {
+  override GlobalVariable::Range range;
+
+  final override GlobalVariableAccess getAnAccess() { result.getVariable() = this }
+}
+
 /** An access to a variable. */
-class VariableAccess extends Expr, @token_identifier {
+class VariableAccess extends Expr {
   override VariableAccess::Range range;
 
   /** Gets the variable this identifier refers to. */
   Variable getVariable() { result = range.getVariable() }
 
   final override string toString() { result = this.getVariable().getName() }
-  // TODO uncomment this and fix the params test
-  //override string getAPrimaryQlClass() { result = "VariableAccess" }
 }
 
 /** An access to a local variable. */
-class LocalVariableAccess extends VariableAccess {
+class LocalVariableAccess extends VariableAccess, @token_identifier {
   final override LocalVariableAccess::Range range;
 
   /** Gets the variable this identifier refers to. */
   final override LocalVariable getVariable() { result = range.getVariable() }
-  // TODO uncomment this and fix the params test
-  //final override string getAPrimaryQlClass() { result = "LocalVariableAccess" }
+
+  final override string getAPrimaryQlClass() {
+    not this instanceof SimpleParameter and result = "LocalVariableAccess"
+  }
+}
+
+/** An access to a local variable. */
+class GlobalVariableAccess extends VariableAccess, @token_global_variable {
+  final override GlobalVariableAccess::Range range;
+
+  /** Gets the variable this identifier refers to. */
+  final override GlobalVariable getVariable() { result = range.getVariable() }
+
+  final override string getAPrimaryQlClass() { result = "GlobalVariableAccess" }
 }
diff --git a/ql/src/codeql_ruby/ast/internal/Variable.qll b/ql/src/codeql_ruby/ast/internal/Variable.qll
index a1fd920231a..8ef650ff1cf 100644
--- a/ql/src/codeql_ruby/ast/internal/Variable.qll
+++ b/ql/src/codeql_ruby/ast/internal/Variable.qll
@@ -101,6 +101,7 @@ cached
 private module Cached {
   cached
   newtype TScope =
+    TGlobalScope() or
     TTopLevelScope(Generated::Program node) or
     TModuleScope(Generated::Module node) or
     TClassScope(AstNode cls) {
@@ -110,6 +111,7 @@ private module Cached {
 
   cached
   newtype TVariable =
+    TGlobalVariable(string name) { name = any(Generated::GlobalVariable var).getValue() } or
     TLocalVariable(VariableScope scope, string name, Generated::Identifier i) {
       scopeDefinesParameterVariable(scope, name, i)
       or
@@ -153,6 +155,14 @@ module VariableScope {
   }
 }
 
+module GlobalScope {
+  class Range extends VariableScope::Range, TGlobalScope {
+    override string toString() { result = "global scope" }
+
+    override AstNode getScopeElement() { none() }
+  }
+}
+
 module TopLevelScope {
   class Range extends VariableScope::Range, TTopLevelScope {
     override string toString() { result = "top-level scope" }
@@ -211,7 +221,7 @@ module Variable {
 }
 
 module LocalVariable {
-  class Range extends Variable::Range {
+  class Range extends Variable::Range, TLocalVariable {
     private VariableScope scope;
     private string name;
     private Generated::Identifier i;
@@ -226,21 +236,43 @@ module LocalVariable {
   }
 }
 
+module GlobalVariable {
+  class Range extends Variable::Range, TGlobalVariable {
+    private string name;
+
+    Range() { this = TGlobalVariable(name) }
+
+    final override string getName() { result = name }
+
+    final override Location getLocation() { none() }
+
+    final override VariableScope getDeclaringScope() { result = TGlobalScope() }
+  }
+}
+
 module VariableAccess {
-  class Range extends Expr::Range, @token_identifier {
-    override Generated::Identifier generated;
-    Variable variable;
-
-    Range() { access(this, variable) }
-
-    Variable getVariable() { result = variable }
+  abstract class Range extends Expr::Range {
+    abstract Variable getVariable();
   }
 }
 
 module LocalVariableAccess {
-  class Range extends VariableAccess::Range {
-    override LocalVariable variable;
+  class Range extends VariableAccess::Range, @token_identifier {
+    override Generated::Identifier generated;
+    LocalVariable variable;
 
-    override LocalVariable getVariable() { result = variable }
+    Range() { access(this, variable) }
+
+    final override LocalVariable getVariable() { result = variable }
+  }
+}
+
+module GlobalVariableAccess {
+  class Range extends VariableAccess::Range, @token_global_variable {
+    GlobalVariable variable;
+
+    Range() { this.(Generated::GlobalVariable).getValue() = variable.getName() }
+
+    final override GlobalVariable getVariable() { result = variable }
   }
 }
diff --git a/ql/test/library-tests/variables/scopes.rb b/ql/test/library-tests/variables/scopes.rb
index 1219acef8cc..65816cc31b4 100644
--- a/ql/test/library-tests/variables/scopes.rb
+++ b/ql/test/library-tests/variables/scopes.rb
@@ -15,4 +15,10 @@ puts a
    puts b # new local variable
    puts c # new local variable
    puts d # new local variable
-end
\ No newline at end of file
+end
+
+# new global variable
+$global = 42
+
+# use of a pre-defined global variable
+script = $0
diff --git a/ql/test/library-tests/variables/varaccess.expected b/ql/test/library-tests/variables/varaccess.expected
index 3c97574dacf..43683ab605d 100644
--- a/ql/test/library-tests/variables/varaccess.expected
+++ b/ql/test/library-tests/variables/varaccess.expected
@@ -76,17 +76,20 @@
 | scopes.rb:2:14:2:14 | x | scopes.rb:2:14:2:14 | x | scopes.rb:2:9:6:3 | block scope |
 | scopes.rb:4:4:4:4 | a | scopes.rb:4:4:4:4 | a | scopes.rb:2:9:6:3 | block scope |
 | scopes.rb:5:9:5:9 | a | scopes.rb:4:4:4:4 | a | scopes.rb:2:9:6:3 | block scope |
-| scopes.rb:7:1:7:1 | a | scopes.rb:7:1:7:1 | a | scopes.rb:1:1:18:3 | top-level scope |
-| scopes.rb:8:6:8:6 | a | scopes.rb:7:1:7:1 | a | scopes.rb:1:1:18:3 | top-level scope |
+| scopes.rb:7:1:7:1 | a | scopes.rb:7:1:7:1 | a | scopes.rb:1:1:24:12 | top-level scope |
+| scopes.rb:8:6:8:6 | a | scopes.rb:7:1:7:1 | a | scopes.rb:1:1:24:12 | top-level scope |
 | scopes.rb:9:14:9:14 | x | scopes.rb:9:14:9:14 | x | scopes.rb:9:9:18:3 | block scope |
-| scopes.rb:10:9:10:9 | a | scopes.rb:7:1:7:1 | a | scopes.rb:1:1:18:3 | top-level scope |
-| scopes.rb:11:4:11:4 | a | scopes.rb:7:1:7:1 | a | scopes.rb:1:1:18:3 | top-level scope |
-| scopes.rb:12:9:12:9 | a | scopes.rb:7:1:7:1 | a | scopes.rb:1:1:18:3 | top-level scope |
-| scopes.rb:13:4:13:4 | a | scopes.rb:7:1:7:1 | a | scopes.rb:1:1:18:3 | top-level scope |
+| scopes.rb:10:9:10:9 | a | scopes.rb:7:1:7:1 | a | scopes.rb:1:1:24:12 | top-level scope |
+| scopes.rb:11:4:11:4 | a | scopes.rb:7:1:7:1 | a | scopes.rb:1:1:24:12 | top-level scope |
+| scopes.rb:12:9:12:9 | a | scopes.rb:7:1:7:1 | a | scopes.rb:1:1:24:12 | top-level scope |
+| scopes.rb:13:4:13:4 | a | scopes.rb:7:1:7:1 | a | scopes.rb:1:1:24:12 | top-level scope |
 | scopes.rb:13:7:13:7 | b | scopes.rb:13:7:13:7 | b | scopes.rb:9:9:18:3 | block scope |
 | scopes.rb:13:11:13:11 | c | scopes.rb:13:11:13:11 | c | scopes.rb:9:9:18:3 | block scope |
 | scopes.rb:13:14:13:14 | d | scopes.rb:13:14:13:14 | d | scopes.rb:9:9:18:3 | block scope |
-| scopes.rb:14:9:14:9 | a | scopes.rb:7:1:7:1 | a | scopes.rb:1:1:18:3 | top-level scope |
+| scopes.rb:14:9:14:9 | a | scopes.rb:7:1:7:1 | a | scopes.rb:1:1:24:12 | top-level scope |
 | scopes.rb:15:9:15:9 | b | scopes.rb:13:7:13:7 | b | scopes.rb:9:9:18:3 | block scope |
 | scopes.rb:16:9:16:9 | c | scopes.rb:13:11:13:11 | c | scopes.rb:9:9:18:3 | block scope |
 | scopes.rb:17:9:17:9 | d | scopes.rb:13:14:13:14 | d | scopes.rb:9:9:18:3 | block scope |
+| scopes.rb:21:1:21:7 | $global | file://:0:0:0:0 | $global | file://:0:0:0:0 | global scope |
+| scopes.rb:24:1:24:6 | script | scopes.rb:24:1:24:6 | script | scopes.rb:1:1:24:12 | top-level scope |
+| scopes.rb:24:10:24:11 | $0 | file://:0:0:0:0 | $0 | file://:0:0:0:0 | global scope |
diff --git a/ql/test/library-tests/variables/variable.expected b/ql/test/library-tests/variables/variable.expected
index 143f5d2639a..749df84cb0d 100644
--- a/ql/test/library-tests/variables/variable.expected
+++ b/ql/test/library-tests/variables/variable.expected
@@ -1,3 +1,5 @@
+| file://:0:0:0:0 | $0 |
+| file://:0:0:0:0 | $global |
 | nested_scopes.rb:5:3:5:3 | a |
 | nested_scopes.rb:7:5:7:5 | a |
 | nested_scopes.rb:9:7:9:7 | a |
@@ -40,3 +42,4 @@
 | scopes.rb:13:7:13:7 | b |
 | scopes.rb:13:11:13:11 | c |
 | scopes.rb:13:14:13:14 | d |
+| scopes.rb:24:1:24:6 | script |
diff --git a/ql/test/library-tests/variables/varscopes.expected b/ql/test/library-tests/variables/varscopes.expected
index 70c2d9283cf..03b586db730 100644
--- a/ql/test/library-tests/variables/varscopes.expected
+++ b/ql/test/library-tests/variables/varscopes.expected
@@ -1,3 +1,4 @@
+| file://:0:0:0:0 | global scope |
 | nested_scopes.rb:1:1:3:3 | method scope |
 | nested_scopes.rb:1:1:42:1 | top-level scope |
 | nested_scopes.rb:4:1:39:3 | class scope |
@@ -25,6 +26,6 @@
 | parameters.rb:49:1:51:3 | method scope |
 | parameters.rb:54:9:57:3 | block scope |
 | scopes.rb:1:1:1:15 | method scope |
-| scopes.rb:1:1:18:3 | top-level scope |
+| scopes.rb:1:1:24:12 | top-level scope |
 | scopes.rb:2:9:6:3 | block scope |
 | scopes.rb:9:9:18:3 | block scope |