diff --git a/dmc-lib/src/ast/call.rs b/dmc-lib/src/ast/call.rs
index bd3dd86..37ce077 100644
--- a/dmc-lib/src/ast/call.rs
+++ b/dmc-lib/src/ast/call.rs
@@ -1,4 +1,5 @@
 use crate::ast::expression::Expression;
+use crate::ast::fqn_util::fqn_parts_to_string;
 use crate::ast::ir_builder::IrBuilder;
 use crate::diagnostic::Diagnostic;
 use crate::ir::ir_call::IrCall;
@@ -186,7 +187,7 @@ impl Call {
         let callable_symbol = self.get_callee_symbol();
         match callable_symbol {
             CallableSymbol::Function(function_symbol) => IrCall::new(
-                function_symbol.borrow().declared_name_owned(),
+                fqn_parts_to_string(function_symbol.borrow().fqn_parts()),
                 arguments,
                 function_symbol.borrow().is_extern(),
             ),
@@ -197,7 +198,7 @@ impl Call {
                     .cloned()
                     .expect("Default constructors not supported yet.");
                 IrCall::new(
-                    constructor_symbol.borrow().declared_name_owned(),
+                    fqn_parts_to_string(constructor_symbol.borrow().fqn_parts()),
                     arguments,
                     false,
                 )
diff --git a/dmc-lib/src/ast/class.rs b/dmc-lib/src/ast/class.rs
index d2834b0..b5927e4 100644
--- a/dmc-lib/src/ast/class.rs
+++ b/dmc-lib/src/ast/class.rs
@@ -1,5 +1,6 @@
 use crate::ast::constructor::Constructor;
 use crate::ast::field::Field;
+use crate::ast::fqn_context::FqnContext;
 use crate::ast::function::Function;
 use crate::diagnostic::{Diagnostic, SecondaryLabel};
 use crate::ir::ir_function::IrFunction;
@@ -40,7 +41,11 @@ impl Class {
     pub fn gather_declared_names(
         &mut self,
         symbol_table: &mut SymbolTable,
+        fqn_context: &mut FqnContext,
     ) -> Result<(), Vec<Diagnostic>> {
+        // 0. Push class name on fqn
+        fqn_context.push(self.declared_name.clone());
+
         // 1. insert class symbol
         let to_insert = ClassSymbol::new(
             &self.declared_name,
@@ -94,7 +99,8 @@ impl Class {
 
         // 4. gather constructor
         if let Some(constructor) = &mut self.constructor {
-            let constructor_symbol = constructor.gather_declared_names(symbol_table)?;
+            let constructor_symbol =
+                constructor.gather_declared_names(symbol_table, fqn_context)?;
             self.class_symbol
                 .as_mut()
                 .unwrap()
@@ -108,7 +114,11 @@ impl Class {
             .functions
             .iter_mut()
             .map(|function| {
-                function.gather_declared_names(symbol_table, self.class_symbol.as_ref())
+                function.gather_declared_names(
+                    symbol_table,
+                    fqn_context,
+                    self.class_symbol.as_ref(),
+                )
             })
             .filter_map(Result::err)
             .flatten()
@@ -121,6 +131,9 @@ impl Class {
         // 6. pop scope
         symbol_table.pop_scope();
 
+        // 7. pop fqn part
+        fqn_context.pop();
+
         Ok(())
     }
 
diff --git a/dmc-lib/src/ast/compilation_unit.rs b/dmc-lib/src/ast/compilation_unit.rs
index c9cde06..0d73d6d 100644
--- a/dmc-lib/src/ast/compilation_unit.rs
+++ b/dmc-lib/src/ast/compilation_unit.rs
@@ -1,5 +1,6 @@
 use crate::ast::class::Class;
 use crate::ast::extern_function::ExternFunction;
+use crate::ast::fqn_context::FqnContext;
 use crate::ast::function::Function;
 use crate::diagnostic::Diagnostic;
 use crate::ir::ir_function::IrFunction;
@@ -42,24 +43,26 @@ impl CompilationUnit {
     ) -> Result<(), Vec<Diagnostic>> {
         symbol_table.push_module_scope("compilation_unit_scope");
 
+        let mut fqn_context = FqnContext::new(); // in the future, we'll push the pkg/ns on here
         let mut diagnostics: Vec<Diagnostic> = vec![];
+
         self.functions
             .iter_mut()
-            .map(|f| f.gather_declared_names(symbol_table, None))
+            .map(|f| f.gather_declared_names(symbol_table, &fqn_context, None))
             .filter_map(Result::err)
             .flatten()
             .for_each(|diagnostic| diagnostics.push(diagnostic));
 
         self.extern_functions
             .iter_mut()
-            .map(|f| f.gather_declared_names(symbol_table))
+            .map(|f| f.gather_declared_names(symbol_table, &fqn_context))
             .filter_map(Result::err)
             .flatten()
             .for_each(|diagnostic| diagnostics.push(diagnostic));
 
         self.classes
             .iter_mut()
-            .map(|c| c.gather_declared_names(symbol_table))
+            .map(|c| c.gather_declared_names(symbol_table, &mut fqn_context))
             .filter_map(Result::err)
             .flatten()
             .for_each(|diagnostic| diagnostics.push(diagnostic));
diff --git a/dmc-lib/src/ast/constructor.rs b/dmc-lib/src/ast/constructor.rs
index 2b409f4..b27b18a 100644
--- a/dmc-lib/src/ast/constructor.rs
+++ b/dmc-lib/src/ast/constructor.rs
@@ -1,4 +1,6 @@
 use crate::ast::field::Field;
+use crate::ast::fqn_context::FqnContext;
+use crate::ast::fqn_util::fqn_parts_to_string;
 use crate::ast::ir_builder::IrBuilder;
 use crate::ast::parameter::Parameter;
 use crate::ast::statement::Statement;
@@ -55,9 +57,14 @@ impl Constructor {
     pub fn gather_declared_names(
         &mut self,
         symbol_table: &mut SymbolTable,
+        fqn_context: &FqnContext,
     ) -> Result<Rc<RefCell<ConstructorSymbol>>, Vec<Diagnostic>> {
         // insert constructor symbol
-        let to_insert = ConstructorSymbol::new(self.ctor_keyword_source_range.clone(), false);
+        let to_insert = ConstructorSymbol::new(
+            self.ctor_keyword_source_range.clone(),
+            fqn_context.resolve("ctor"), // ctor is a keyword at the language level, should not be callable via normal means
+            false,
+        );
         let constructor_symbol =
             symbol_table
                 .insert_constructor_symbol(to_insert)
@@ -277,8 +284,15 @@ impl Constructor {
         let entry_block = ir_builder.get_block(entry_block_id);
 
         IrFunction::new(
-            format!("{}::ctor", class_symbol.borrow().declared_name()).into(), // fake function symbol
-            &ir_parameters,                                                    // make params
+            fqn_parts_to_string(
+                class_symbol
+                    .borrow()
+                    .constructor_symbol()
+                    .unwrap()
+                    .borrow()
+                    .fqn_parts(),
+            ), // fake function symbol
+            &ir_parameters, // make params
             &TypeInfo::ClassInstance(class_symbol.clone()),
             entry_block.clone(),
         )
diff --git a/dmc-lib/src/ast/extern_function.rs b/dmc-lib/src/ast/extern_function.rs
index 6026b0f..1495fd1 100644
--- a/dmc-lib/src/ast/extern_function.rs
+++ b/dmc-lib/src/ast/extern_function.rs
@@ -1,3 +1,4 @@
+use crate::ast::fqn_context::FqnContext;
 use crate::ast::parameter::Parameter;
 use crate::ast::type_use::TypeUse;
 use crate::diagnostic::Diagnostic;
@@ -39,12 +40,14 @@ impl ExternFunction {
     pub fn gather_declared_names(
         &mut self,
         symbol_table: &mut SymbolTable,
+        fqn_context: &FqnContext,
     ) -> Result<(), Vec<Diagnostic>> {
         let mut diagnostics = vec![];
 
         let insert_result = symbol_table.insert_function_symbol(FunctionSymbol::new(
             &self.declared_name,
             self.declared_name_source_range.clone(),
+            fqn_context.resolve(self.declared_name()),
             true,
         ));
 
diff --git a/dmc-lib/src/ast/fqn_context.rs b/dmc-lib/src/ast/fqn_context.rs
new file mode 100644
index 0000000..ee39d8c
--- /dev/null
+++ b/dmc-lib/src/ast/fqn_context.rs
@@ -0,0 +1,25 @@
+use std::rc::Rc;
+
+pub struct FqnContext {
+    parts: Vec<Rc<str>>,
+}
+
+impl FqnContext {
+    pub fn new() -> Self {
+        Self { parts: vec![] }
+    }
+
+    pub fn push(&mut self, part: Rc<str>) {
+        self.parts.push(part);
+    }
+
+    pub fn pop(&mut self) {
+        self.parts.pop();
+    }
+
+    pub fn resolve(&self, name: &str) -> Vec<Rc<str>> {
+        let mut result = self.parts.clone();
+        result.push(name.into());
+        result
+    }
+}
diff --git a/dmc-lib/src/ast/fqn_util.rs b/dmc-lib/src/ast/fqn_util.rs
new file mode 100644
index 0000000..d9b78c2
--- /dev/null
+++ b/dmc-lib/src/ast/fqn_util.rs
@@ -0,0 +1,6 @@
+use std::rc::Rc;
+
+#[inline]
+pub fn fqn_parts_to_string(parts: &[Rc<str>]) -> Rc<str> {
+    parts.join("::").into()
+}
diff --git a/dmc-lib/src/ast/function.rs b/dmc-lib/src/ast/function.rs
index 6f63f8c..c799421 100644
--- a/dmc-lib/src/ast/function.rs
+++ b/dmc-lib/src/ast/function.rs
@@ -1,3 +1,5 @@
+use crate::ast::fqn_context::FqnContext;
+use crate::ast::fqn_util::fqn_parts_to_string;
 use crate::ast::ir_builder::IrBuilder;
 use crate::ast::parameter::Parameter;
 use crate::ast::statement::Statement;
@@ -7,9 +9,9 @@ use crate::ir::ir_function::IrFunction;
 use crate::ir::ir_parameter::IrParameter;
 use crate::ir::ir_parameter_or_variable::IrParameterOrVariable;
 use crate::source_range::SourceRange;
+use crate::symbol::Symbol;
 use crate::symbol::class_symbol::ClassSymbol;
 use crate::symbol::function_symbol::FunctionSymbol;
-use crate::symbol::Symbol;
 use crate::symbol_table::{SymbolInsertError, SymbolTable};
 use crate::type_info::TypeInfo;
 use std::cell::RefCell;
@@ -57,6 +59,7 @@ impl Function {
     pub fn gather_declared_names(
         &mut self,
         symbol_table: &mut SymbolTable,
+        fqn_context: &FqnContext,
         class_context: Option<&Rc<RefCell<ClassSymbol>>>,
     ) -> Result<(), Vec<Diagnostic>> {
         let mut diagnostics = vec![];
@@ -69,6 +72,7 @@ impl Function {
         let insert_result = symbol_table.insert_function_symbol(FunctionSymbol::new(
             self.declared_name(),
             self.declared_name_source_range.clone(),
+            fqn_context.resolve(self.declared_name()),
             false,
         ));
 
@@ -304,11 +308,7 @@ impl Function {
 
         let entry_block = builder.get_block(entry_block_id).clone();
         IrFunction::new(
-            self.function_symbol
-                .as_ref()
-                .unwrap()
-                .borrow()
-                .declared_name_owned(), // ok for now... but we need to start using the fqn
+            fqn_parts_to_string(self.function_symbol.as_ref().unwrap().borrow().fqn_parts()),
             builder.parameters(),
             return_type_info,
             entry_block,
diff --git a/dmc-lib/src/ast/mod.rs b/dmc-lib/src/ast/mod.rs
index 234768e..8d52256 100644
--- a/dmc-lib/src/ast/mod.rs
+++ b/dmc-lib/src/ast/mod.rs
@@ -9,6 +9,8 @@ pub mod expression_statement;
 pub mod extern_function;
 pub mod field;
 pub mod fqn;
+pub mod fqn_context;
+mod fqn_util;
 pub mod function;
 pub mod identifier;
 pub mod integer_literal;
diff --git a/dmc-lib/src/symbol/constructor_symbol.rs b/dmc-lib/src/symbol/constructor_symbol.rs
index 057e719..cb3425c 100644
--- a/dmc-lib/src/symbol/constructor_symbol.rs
+++ b/dmc-lib/src/symbol/constructor_symbol.rs
@@ -6,19 +6,29 @@ use std::rc::Rc;
 
 pub struct ConstructorSymbol {
     ctor_keyword_source_range: SourceRange,
+    fqn_parts: Vec<Rc<str>>,
     is_extern: bool,
     parameters: Option<Vec<Rc<RefCell<ParameterSymbol>>>>,
 }
 
 impl ConstructorSymbol {
-    pub fn new(ctor_keyword_source_range: SourceRange, is_extern: bool) -> Self {
+    pub fn new(
+        ctor_keyword_source_range: SourceRange,
+        fqn_parts: Vec<Rc<str>>,
+        is_extern: bool,
+    ) -> Self {
         Self {
             ctor_keyword_source_range,
+            fqn_parts,
             is_extern,
             parameters: None,
         }
     }
 
+    pub fn fqn_parts(&self) -> &[Rc<str>] {
+        &self.fqn_parts
+    }
+
     pub fn set_parameters(&mut self, parameters: Vec<Rc<RefCell<ParameterSymbol>>>) {
         self.parameters = Some(parameters);
     }
diff --git a/dmc-lib/src/symbol/function_symbol.rs b/dmc-lib/src/symbol/function_symbol.rs
index 74c7974..44249f0 100644
--- a/dmc-lib/src/symbol/function_symbol.rs
+++ b/dmc-lib/src/symbol/function_symbol.rs
@@ -8,6 +8,7 @@ use std::rc::Rc;
 pub struct FunctionSymbol {
     declared_name: Rc<str>,
     declared_name_source_range: SourceRange,
+    fqn_parts: Vec<Rc<str>>,
     is_extern: bool,
     parameters: Option<Vec<Rc<RefCell<ParameterSymbol>>>>,
     return_type: Option<TypeInfo>,
@@ -17,17 +18,23 @@ impl FunctionSymbol {
     pub fn new(
         declared_name: &str,
         declared_name_source_range: SourceRange,
+        fqn_parts: Vec<Rc<str>>,
         is_extern: bool,
     ) -> Self {
         Self {
             declared_name: declared_name.into(),
             declared_name_source_range,
+            fqn_parts,
             is_extern,
             parameters: None,
             return_type: None,
         }
     }
 
+    pub fn fqn_parts(&self) -> &[Rc<str>] {
+        &self.fqn_parts
+    }
+
     pub fn set_parameters(&mut self, parameters: Vec<Rc<RefCell<ParameterSymbol>>>) {
         self.parameters = Some(parameters);
     }