diff --git a/compiler/cl-ast/src/ast.rs b/compiler/cl-ast/src/ast.rs
index b9e9fff..9c4f4a0 100644
--- a/compiler/cl-ast/src/ast.rs
+++ b/compiler/cl-ast/src/ast.rs
@@ -253,12 +253,27 @@ pub enum TyKind {
     Never,
     Empty,
     Path(Path),
+    Array(TyArray),
+    Slice(TySlice),
     Tuple(TyTuple),
     Ref(TyRef),
     Fn(TyFn),
     // TODO: slice, array types
 }
 
+/// An array of [`T`](Ty)
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct TyArray {
+    pub ty: Box<TyKind>,
+    pub count: usize,
+}
+
+/// A [Ty]pe slice expression: `[T]`
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct TySlice {
+    pub ty: Box<TyKind>,
+}
+
 /// A tuple of [Ty]pes
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct TyTuple {
diff --git a/compiler/cl-ast/src/ast_impl.rs b/compiler/cl-ast/src/ast_impl.rs
index 0006f4b..22213d6 100644
--- a/compiler/cl-ast/src/ast_impl.rs
+++ b/compiler/cl-ast/src/ast_impl.rs
@@ -307,6 +307,8 @@ mod display {
                 TyKind::Never => "!".fmt(f),
                 TyKind::Empty => "()".fmt(f),
                 TyKind::Path(v) => v.fmt(f),
+                TyKind::Array(v) => v.fmt(f),
+                TyKind::Slice(v) => v.fmt(f),
                 TyKind::Tuple(v) => v.fmt(f),
                 TyKind::Ref(v) => v.fmt(f),
                 TyKind::Fn(v) => v.fmt(f),
@@ -314,6 +316,20 @@ mod display {
         }
     }
 
+    impl Display for TyArray {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            let Self { ty, count } = self;
+            write!(f, "[{ty}; {count}]")
+        }
+    }
+
+    impl Display for TySlice {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            let Self { ty } = self;
+            write!(f, "[{ty}]")
+        }
+    }
+
     impl Display for TyTuple {
         fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             separate(&self.types, ", ")(f.delimit(INLINE_PARENS))
diff --git a/compiler/cl-ast/src/ast_visitor/fold.rs b/compiler/cl-ast/src/ast_visitor/fold.rs
index c2613ee..1835a62 100644
--- a/compiler/cl-ast/src/ast_visitor/fold.rs
+++ b/compiler/cl-ast/src/ast_visitor/fold.rs
@@ -172,6 +172,14 @@ pub trait Fold {
     fn fold_ty_kind(&mut self, kind: TyKind) -> TyKind {
         or_fold_ty_kind(self, kind)
     }
+    fn fold_ty_array(&mut self, a: TyArray) -> TyArray {
+        let TyArray { ty, count } = a;
+        TyArray { ty: Box::new(self.fold_ty_kind(*ty)), count }
+    }
+    fn fold_ty_slice(&mut self, s: TySlice) -> TySlice {
+        let TySlice { ty } = s;
+        TySlice { ty: Box::new(self.fold_ty_kind(*ty)) }
+    }
     fn fold_ty_tuple(&mut self, t: TyTuple) -> TyTuple {
         let TyTuple { types } = t;
         TyTuple {
@@ -500,6 +508,8 @@ pub fn or_fold_ty_kind<F: Fold + ?Sized>(folder: &mut F, kind: TyKind) -> TyKind
         TyKind::Never => TyKind::Never,
         TyKind::Empty => TyKind::Empty,
         TyKind::Path(p) => TyKind::Path(folder.fold_path(p)),
+        TyKind::Array(a) => TyKind::Array(folder.fold_ty_array(a)),
+        TyKind::Slice(s) => TyKind::Slice(folder.fold_ty_slice(s)),
         TyKind::Tuple(t) => TyKind::Tuple(folder.fold_ty_tuple(t)),
         TyKind::Ref(t) => TyKind::Ref(folder.fold_ty_ref(t)),
         TyKind::Fn(t) => TyKind::Fn(folder.fold_ty_fn(t)),
diff --git a/compiler/cl-ast/src/ast_visitor/visit.rs b/compiler/cl-ast/src/ast_visitor/visit.rs
index 0efbc3b..3a49b42 100644
--- a/compiler/cl-ast/src/ast_visitor/visit.rs
+++ b/compiler/cl-ast/src/ast_visitor/visit.rs
@@ -145,6 +145,14 @@ pub trait Visit<'a>: Sized {
     fn visit_ty_kind(&mut self, kind: &'a TyKind) {
         or_visit_ty_kind(self, kind)
     }
+    fn visit_ty_array(&mut self, a: &'a TyArray) {
+        let TyArray { ty, count: _ } = a;
+        self.visit_ty_kind(ty);
+    }
+    fn visit_ty_slice(&mut self, s: &'a TySlice) {
+        let TySlice { ty } = s;
+        self.visit_ty_kind(ty)
+    }
     fn visit_ty_tuple(&mut self, t: &'a TyTuple) {
         let TyTuple { types } = t;
         types.iter().for_each(|kind| self.visit_ty_kind(kind))
@@ -424,6 +432,8 @@ pub fn or_visit_ty_kind<'a, V: Visit<'a>>(visitor: &mut V, kind: &'a TyKind) {
         TyKind::Never => {}
         TyKind::Empty => {}
         TyKind::Path(p) => visitor.visit_path(p),
+        TyKind::Array(t) => visitor.visit_ty_array(t),
+        TyKind::Slice(t) => visitor.visit_ty_slice(t),
         TyKind::Tuple(t) => visitor.visit_ty_tuple(t),
         TyKind::Ref(t) => visitor.visit_ty_ref(t),
         TyKind::Fn(t) => visitor.visit_ty_fn(t),
diff --git a/compiler/cl-parser/src/error.rs b/compiler/cl-parser/src/error.rs
index 0661ad5..1335cab 100644
--- a/compiler/cl-parser/src/error.rs
+++ b/compiler/cl-parser/src/error.rs
@@ -78,6 +78,8 @@ pub enum Parsing {
 
     Ty,
     TyKind,
+    TySlice,
+    TyArray,
     TyTuple,
     TyRef,
     TyFn,
@@ -181,13 +183,15 @@ impl Display for Parsing {
 
             Parsing::Ty => "a type",
             Parsing::TyKind => "a type",
+            Parsing::TySlice => "a slice type",
+            Parsing::TyArray => "an array type",
             Parsing::TyTuple => "a tuple of types",
             Parsing::TyRef => "a reference type",
             Parsing::TyFn => "a function pointer type",
 
             Parsing::Path => "a path",
             Parsing::PathPart => "a path component",
-            
+
             Parsing::Stmt => "a statement",
             Parsing::StmtKind => "a statement",
             Parsing::Let => "a local variable declaration",
diff --git a/compiler/cl-parser/src/parser.rs b/compiler/cl-parser/src/parser.rs
index 7072667..02db1f1 100644
--- a/compiler/cl-parser/src/parser.rs
+++ b/compiler/cl-parser/src/parser.rs
@@ -673,6 +673,7 @@ impl<'t> Parser<'t> {
                 TyKind::Never
             }
             TokenKind::Punct(Punct::Amp) | TokenKind::Punct(Punct::AmpAmp) => self.tyref()?.into(),
+            TokenKind::Punct(Punct::LBrack) => self.tyslice_or_array()?,
             TokenKind::Punct(Punct::LParen) => {
                 let out = self.tytuple()?;
                 match out.types.is_empty() {
@@ -687,6 +688,32 @@ impl<'t> Parser<'t> {
 
         Ok(out)
     }
+
+    /// [`TySlice`] = `[` [Ty] `]`  \
+    /// [`TyArray`] = `[` [Ty] `;` [usize] `]`
+    pub fn tyslice_or_array(&mut self) -> PResult<TyKind> {
+        self.match_op(BRACKETS.0, Parsing::TySlice)?;
+        let ty = self.tykind()?;
+        let (out, kind) = match self.match_op(Punct::Semi, Parsing::TyArray).is_ok() {
+            true => {
+                let literal = self.match_type(TokenKind::Literal, Parsing::TyArray)?;
+                let &TokenData::Integer(count) = literal.data() else {
+                    Err(self.error(Unexpected(TokenKind::Literal), Parsing::TyArray))?
+                };
+                (
+                    TyKind::Array(TyArray { ty: Box::new(ty), count: count as _ }),
+                    Parsing::TyArray,
+                )
+            }
+            false => (
+                TyKind::Slice(TySlice { ty: Box::new(ty) }),
+                Parsing::TySlice,
+            ),
+        };
+        self.match_op(BRACKETS.1, kind)?;
+        Ok(out)
+    }
+
     /// [TyTuple] = `(` ([Ty] `,`)* [Ty]? `)`
     pub fn tytuple(&mut self) -> PResult<TyTuple> {
         const PARSING: Parsing = Parsing::TyTuple;
diff --git a/compiler/cl-repl/examples/yaml.rs b/compiler/cl-repl/examples/yaml.rs
index af5e5e0..03b3495 100644
--- a/compiler/cl-repl/examples/yaml.rs
+++ b/compiler/cl-repl/examples/yaml.rs
@@ -614,6 +614,8 @@ pub mod yamlify {
                 TyKind::Tuple(t) => y.yaml(t),
                 TyKind::Ref(t) => y.yaml(t),
                 TyKind::Fn(t) => y.yaml(t),
+                TyKind::Slice(_) => todo!(),
+                TyKind::Array(_) => todo!(),
             };
         }
     }
@@ -639,6 +641,18 @@ pub mod yamlify {
             };
         }
     }
+    impl Yamlify for TyArray {
+        fn yaml(&self, y: &mut Yamler) {
+            let Self { ty, count } = self;
+            y.key("TyArray").pair("ty", ty).pair("count", count);
+        }
+    }
+    impl Yamlify for TySlice {
+        fn yaml(&self, y: &mut Yamler) {
+            let Self { ty } = self;
+            y.key("TyArray").pair("ty", ty);
+        }
+    }
     impl Yamlify for TyTuple {
         fn yaml(&self, y: &mut Yamler) {
             let Self { types } = self;
diff --git a/compiler/cl-typeck/src/project.rs b/compiler/cl-typeck/src/project.rs
index e55892f..58cdc08 100644
--- a/compiler/cl-typeck/src/project.rs
+++ b/compiler/cl-typeck/src/project.rs
@@ -172,7 +172,7 @@ pub mod evaluate {
 
     use super::*;
     use crate::module;
-    use cl_ast::{Sym, Ty, TyFn, TyKind, TyRef, TyTuple};
+    use cl_ast::{Sym, Ty, TyArray, TyFn, TyKind, TyRef, TySlice, TyTuple};
 
     /// Things that can be evaluated as a type expression
     pub trait EvaluableTypeExpression {
@@ -197,6 +197,8 @@ pub mod evaluate {
                 TyKind::Empty => prj.anon_types[&TypeKind::Empty],
                 // TyKind::Path must be looked up explicitly
                 TyKind::Path(path) => path.evaluate(prj, parent)?,
+                TyKind::Slice(slice) => slice.evaluate(prj, parent)?,
+                TyKind::Array(array) => array.evaluate(prj, parent)?,
                 TyKind::Tuple(tup) => tup.evaluate(prj, parent)?,
                 TyKind::Ref(tyref) => tyref.evaluate(prj, parent)?,
                 TyKind::Fn(tyfn) => tyfn.evaluate(prj, parent)?,
@@ -220,6 +222,38 @@ pub mod evaluate {
         }
     }
 
+    impl EvaluableTypeExpression for TySlice {
+        type Out = DefID;
+
+        fn evaluate(&self, prj: &mut Project, parent: DefID) -> Result<Self::Out, String> {
+            let ty = self.ty.evaluate(prj, parent)?;
+            let root = prj.root;
+            let id = prj.insert_anonymous_type(TypeKind::Slice(ty), move || Def {
+                module: module::Module::new(root),
+                node: Node::new(Default::default(), None),
+                kind: DefKind::Type(TypeKind::Slice(ty)),
+            });
+
+            Ok(id)
+        }
+    }
+
+    impl EvaluableTypeExpression for TyArray {
+        type Out = DefID;
+
+        fn evaluate(&self, prj: &mut Project, parent: DefID) -> Result<Self::Out, String> {
+            let kind = TypeKind::Array(self.ty.evaluate(prj, parent)?, self.count);
+            let root = prj.root;
+            let id = prj.insert_anonymous_type(kind.clone(), move || Def {
+                module: module::Module::new(root),
+                node: Node::new(Default::default(), None),
+                kind: DefKind::Type(kind),
+            });
+
+            Ok(id)
+        }
+    }
+
     impl EvaluableTypeExpression for TyTuple {
         type Out = DefID;
         fn evaluate(&self, prj: &mut Project, parent: DefID) -> Result<DefID, String> {
diff --git a/grammar.ebnf b/grammar.ebnf
index 0b02668..fbaf21e 100644
--- a/grammar.ebnf
+++ b/grammar.ebnf
@@ -50,10 +50,12 @@ UseTree     = '*' | '{' (UseTree ',')* UseTree? '}'
             | PathPart ('::' UseTree | "as" Identifier)? ;
 
 (* type *)
-Ty          = Never | Empty | Path | TyTuple | TyRef | TyFn ;
+Ty          = Never | Empty | Path | TyArray | TySlice | TyTuple | TyRef | TyFn ;
 Never       = '!' ;
 Empty       = '(' ')' ;
 TyTuple     = '(' (Ty ',')* Ty? ')' ;
+TyArray     = '[' Ty ';' INTEGER ']' ;
+TySlice     = '[' Ty ']' ;
 TyRef       = Amps* Path ;
 Amps        = '&' | '&&' ;
 TyFn        = "fn" TyTuple ('->' Ty)? ;