diff --git a/contracts-proc/src/interface.rs b/contracts-proc/src/interface_id.rs
similarity index 96%
rename from contracts-proc/src/interface.rs
rename to contracts-proc/src/interface_id.rs
index 6fa40c4b..d791dde7 100644
--- a/contracts-proc/src/interface.rs
+++ b/contracts-proc/src/interface_id.rs
@@ -10,7 +10,10 @@ use syn::{
 };
 
 /// Computes interface id as an associated constant for the trait.
-pub(crate) fn interface(_attr: TokenStream, input: TokenStream) -> TokenStream {
+pub(crate) fn interface_id(
+    _attr: &TokenStream,
+    input: TokenStream,
+) -> TokenStream {
     let mut input = parse_macro_input!(input as ItemTrait);
     let mut output = quote! {};
 
@@ -48,7 +51,7 @@ pub(crate) fn interface(_attr: TokenStream, input: TokenStream) -> TokenStream {
         let arg_types: Vec<_> = args
             .filter_map(|arg| match arg {
                 FnArg::Typed(t) => Some(t.ty.clone()),
-                _ => None,
+                FnArg::Receiver(_) => None,
             })
             .collect();
 
diff --git a/contracts-proc/src/lib.rs b/contracts-proc/src/lib.rs
index 6060d236..470488d3 100644
--- a/contracts-proc/src/lib.rs
+++ b/contracts-proc/src/lib.rs
@@ -1,9 +1,12 @@
-// TODO#q: add crate documentation.
+//! Procedural macro definitions used in `openzeppelin-stylus` smart contracts
+//! library.
 
 extern crate proc_macro;
 use proc_macro::TokenStream;
 
 /// Shorthand to print nice errors.
+///
+/// Note that it's defined before the module declarations.
 macro_rules! error {
     ($tokens:expr, $($msg:expr),+ $(,)?) => {{
         let error = syn::Error::new(syn::spanned::Spanned::span(&$tokens), format!($($msg),+));
@@ -14,10 +17,47 @@ macro_rules! error {
     }};
 }
 
-mod interface;
+mod interface_id;
 
-/// Computes interface id as an associated constant for the trait.
+/// Computes interface id as an associated constant `INTERFACE_ID` for the
+/// trait that describes contract's abi.
+/// Selector collision should be handled with macro `#[selector(name =
+/// "actualSolidityMethodName")]` on top of the method.
+///
+/// # Examples
+///
+/// ```rust,ignore
+/// #[interface_id]
+/// pub trait IErc721 {
+///     fn balance_of(&self, owner: Address) -> Result<U256, alloc::vec::Vec<u8>>;
+///
+///     fn owner_of(&self, token_id: U256) -> Result<Address, alloc::vec::Vec<u8>>;
+///
+///     fn safe_transfer_from(
+///         &mut self,
+///         from: Address,
+///         to: Address,
+///         token_id: U256,
+///     ) -> Result<(), alloc::vec::Vec<u8>>;
+///
+///     #[selector(name = "safeTransferFrom")]
+///     fn safe_transfer_from_with_data(
+///         &mut self,
+///         from: Address,
+///         to: Address,
+///         token_id: U256,
+///         data: Bytes,
+///     ) -> Result<(), alloc::vec::Vec<u8>>;
+/// }
+///
+/// impl IErc165 for Erc721 {
+///     fn supports_interface(interface_id: FixedBytes<4>) -> bool {
+///         <Self as IErc721>::INTERFACE_ID == u32::from_be_bytes(*interface_id)
+///             || Erc165::supports_interface(interface_id)
+///     }
+/// }
+/// ```
 #[proc_macro_attribute]
-pub fn interface(attr: TokenStream, input: TokenStream) -> TokenStream {
-    interface::interface(attr, input)
+pub fn interface_id(attr: TokenStream, input: TokenStream) -> TokenStream {
+    interface_id::interface_id(&attr, input)
 }
diff --git a/contracts/src/token/erc20/extensions/metadata.rs b/contracts/src/token/erc20/extensions/metadata.rs
index 4035f558..1ab47a2d 100644
--- a/contracts/src/token/erc20/extensions/metadata.rs
+++ b/contracts/src/token/erc20/extensions/metadata.rs
@@ -2,8 +2,12 @@
 
 use alloc::string::String;
 
+use alloy_primitives::FixedBytes;
+use openzeppelin_stylus_proc::interface_id;
 use stylus_proc::{public, sol_storage};
 
+use crate::utils::introspection::erc165::IErc165;
+
 /// Number of decimals used by default on implementors of [`Metadata`].
 pub const DEFAULT_DECIMALS: u8 = 18;
 
@@ -20,6 +24,7 @@ sol_storage! {
 }
 
 /// Interface for the optional metadata functions from the ERC-20 standard.
+#[interface_id]
 pub trait IErc20Metadata {
     /// Returns the name of the token.
     ///
@@ -76,3 +81,10 @@ impl IErc20Metadata for Erc20Metadata {
         DEFAULT_DECIMALS
     }
 }
+
+impl IErc165 for Erc20Metadata {
+    fn supports_interface(interface_id: FixedBytes<4>) -> bool {
+        <Self as IErc20Metadata>::INTERFACE_ID
+            == u32::from_be_bytes(*interface_id)
+    }
+}
diff --git a/contracts/src/token/erc20/mod.rs b/contracts/src/token/erc20/mod.rs
index 33a9fa29..b1b069d5 100644
--- a/contracts/src/token/erc20/mod.rs
+++ b/contracts/src/token/erc20/mod.rs
@@ -4,9 +4,9 @@
 //! revert instead of returning `false` on failure. This behavior is
 //! nonetheless conventional and does not conflict with the expectations of
 //! [`Erc20`] applications.
-use alloy_primitives::{Address, U256};
+use alloy_primitives::{Address, FixedBytes, U256};
 use alloy_sol_types::sol;
-use openzeppelin_stylus_proc::interface;
+use openzeppelin_stylus_proc::interface_id;
 use stylus_proc::SolidityError;
 use stylus_sdk::{
     call::MethodError,
@@ -14,6 +14,8 @@ use stylus_sdk::{
     stylus_proc::{public, sol_storage},
 };
 
+use crate::utils::introspection::erc165::{Erc165, IErc165};
+
 pub mod extensions;
 
 sol! {
@@ -112,7 +114,7 @@ sol_storage! {
 }
 
 /// Required interface of an [`Erc20`] compliant contract.
-#[interface]
+#[interface_id]
 pub trait IErc20 {
     /// The error type associated to this ERC-20 trait implementation.
     type Error: Into<alloc::vec::Vec<u8>>;
@@ -288,6 +290,13 @@ impl IErc20 for Erc20 {
     }
 }
 
+impl IErc165 for Erc20 {
+    fn supports_interface(interface_id: FixedBytes<4>) -> bool {
+        <Self as IErc20>::INTERFACE_ID == u32::from_be_bytes(*interface_id)
+            || Erc165::supports_interface(interface_id)
+    }
+}
+
 impl Erc20 {
     /// Sets a `value` number of tokens as the allowance of `spender` over the
     /// caller's tokens.
@@ -552,7 +561,10 @@ mod tests {
     use stylus_sdk::msg;
 
     use super::{Erc20, Error, IErc20};
-    use crate::token::erc721::{Erc721, IErc721};
+    use crate::{
+        token::erc721::{Erc721, IErc721},
+        utils::introspection::erc165::IErc165,
+    };
 
     #[motsu::test]
     fn reads_balance(contract: Erc20) {
@@ -889,7 +901,11 @@ mod tests {
     #[motsu::test]
     fn interface_id() {
         let actual = <Erc20 as IErc20>::INTERFACE_ID;
-        let expected = 0x_36372b07;
+        let expected = 0x36372b07;
+        assert_eq!(actual, expected);
+
+        let actual = <Erc20 as IErc165>::INTERFACE_ID;
+        let expected = 0x01ffc9a7;
         assert_eq!(actual, expected);
     }
 }
diff --git a/contracts/src/token/erc721/extensions/enumerable.rs b/contracts/src/token/erc721/extensions/enumerable.rs
index 263f676a..6bfa3a73 100644
--- a/contracts/src/token/erc721/extensions/enumerable.rs
+++ b/contracts/src/token/erc721/extensions/enumerable.rs
@@ -10,11 +10,15 @@
 //! [`Erc721Enumerable`].
 // TODO: Add link for `Erc721Consecutive` to module docs.
 
-use alloy_primitives::{uint, Address, U256};
+use alloy_primitives::{uint, Address, FixedBytes, U256};
 use alloy_sol_types::sol;
+use openzeppelin_stylus_proc::interface_id;
 use stylus_proc::{public, sol_storage, SolidityError};
 
-use crate::token::{erc721, erc721::IErc721};
+use crate::{
+    token::{erc721, erc721::IErc721},
+    utils::introspection::erc165::IErc165,
+};
 
 sol! {
     /// Indicates an error when an `owner`'s token query
@@ -63,6 +67,7 @@ sol_storage! {
 
 /// This is the interface of the optional `Enumerable` extension
 /// of the ERC-721 standard.
+#[interface_id]
 pub trait IErc721Enumerable {
     /// The error type associated to this ERC-721 enumerable trait
     /// implementation.
@@ -144,6 +149,13 @@ impl IErc721Enumerable for Erc721Enumerable {
     }
 }
 
+impl IErc165 for Erc721Enumerable {
+    fn supports_interface(interface_id: FixedBytes<4>) -> bool {
+        <Self as IErc721Enumerable>::INTERFACE_ID
+            == u32::from_be_bytes(*interface_id)
+    }
+}
+
 impl Erc721Enumerable {
     /// Function to add a token to this extension's
     /// ownership-tracking data structures.
diff --git a/contracts/src/token/erc721/extensions/metadata.rs b/contracts/src/token/erc721/extensions/metadata.rs
index 5b315bf4..3e20bfdc 100644
--- a/contracts/src/token/erc721/extensions/metadata.rs
+++ b/contracts/src/token/erc721/extensions/metadata.rs
@@ -2,9 +2,14 @@
 
 use alloc::string::String;
 
+use alloy_primitives::FixedBytes;
+use openzeppelin_stylus_proc::interface_id;
 use stylus_proc::{public, sol_storage};
 
-use crate::utils::Metadata;
+use crate::{
+    token::erc20::extensions::IErc20Metadata,
+    utils::{introspection::erc165::IErc165, Metadata},
+};
 
 sol_storage! {
     /// Metadata of an [`crate::token::erc721::Erc721`] token.
@@ -17,6 +22,7 @@ sol_storage! {
 }
 
 /// Interface for the optional metadata functions from the ERC-721 standard.
+#[interface_id]
 pub trait IErc721Metadata {
     /// Returns the token collection name.
     ///
@@ -58,3 +64,10 @@ impl IErc721Metadata for Erc721Metadata {
         self._base_uri.get_string()
     }
 }
+
+impl IErc165 for Erc721Metadata {
+    fn supports_interface(interface_id: FixedBytes<4>) -> bool {
+        <Self as IErc721Metadata>::INTERFACE_ID
+            == u32::from_be_bytes(*interface_id)
+    }
+}
diff --git a/contracts/src/token/erc721/mod.rs b/contracts/src/token/erc721/mod.rs
index 91d45eb6..c88262b1 100644
--- a/contracts/src/token/erc721/mod.rs
+++ b/contracts/src/token/erc721/mod.rs
@@ -2,7 +2,7 @@
 use alloc::vec;
 
 use alloy_primitives::{fixed_bytes, uint, Address, FixedBytes, U128, U256};
-use openzeppelin_stylus_proc::interface;
+use openzeppelin_stylus_proc::interface_id;
 use stylus_sdk::{
     abi::Bytes,
     alloy_sol_types::sol,
@@ -11,7 +11,10 @@ use stylus_sdk::{
     prelude::*,
 };
 
-use crate::utils::math::storage::{AddAssignUnchecked, SubAssignUnchecked};
+use crate::utils::{
+    introspection::erc165::{Erc165, IErc165},
+    math::storage::{AddAssignUnchecked, SubAssignUnchecked},
+};
 
 pub mod extensions;
 
@@ -199,7 +202,7 @@ sol_storage! {
 unsafe impl TopLevelStorage for Erc721 {}
 
 /// Required interface of an [`Erc721`] compliant contract.
-#[interface]
+#[interface_id]
 pub trait IErc721 {
     /// The error type associated to this ERC-721 trait implementation.
     type Error: Into<alloc::vec::Vec<u8>>;
@@ -552,6 +555,13 @@ impl IErc721 for Erc721 {
     }
 }
 
+impl IErc165 for Erc721 {
+    fn supports_interface(interface_id: FixedBytes<4>) -> bool {
+        <Self as IErc721>::INTERFACE_ID == u32::from_be_bytes(*interface_id)
+            || Erc165::supports_interface(interface_id)
+    }
+}
+
 impl Erc721 {
     /// Returns the owner of the `token_id`. Does NOT revert if the token
     /// doesn't exist.
@@ -1156,6 +1166,7 @@ mod tests {
         ERC721InvalidReceiver, ERC721InvalidSender, ERC721NonexistentToken,
         Erc721, Error, IErc721,
     };
+    use crate::utils::introspection::erc165::IErc165;
 
     const BOB: Address = address!("F4EaCDAbEf3c8f1EdE91b6f2A6840bc2E4DD3526");
     const DAVE: Address = address!("0BB78F7e7132d1651B4Fd884B7624394e92156F1");
@@ -2494,7 +2505,11 @@ mod tests {
     #[motsu::test]
     fn interface_id() {
         let actual = <Erc721 as IErc721>::INTERFACE_ID;
-        let expected = 0x_80ac58cd;
+        let expected = 0x80ac58cd;
+        assert_eq!(actual, expected);
+
+        let actual = <Erc721 as IErc165>::INTERFACE_ID;
+        let expected = 0x01ffc9a7;
         assert_eq!(actual, expected);
     }
 }
diff --git a/contracts/src/utils/introspection/erc165.rs b/contracts/src/utils/introspection/erc165.rs
new file mode 100644
index 00000000..38a8401b
--- /dev/null
+++ b/contracts/src/utils/introspection/erc165.rs
@@ -0,0 +1,64 @@
+//! Trait and implementation of the ERC-165 standard, as defined in the [ERC].
+//!
+//! [ERC]: https://eips.ethereum.org/EIPS/eip-165
+
+use alloy_primitives::FixedBytes;
+use openzeppelin_stylus_proc::interface_id;
+
+/// Interface of the ERC-165 standard, as defined in the [ERC].
+///
+/// Implementers can declare support of contract interfaces, which others can
+/// query.
+///
+/// For an implementation, see [`Erc165`].
+///
+/// [ERC]: https://eips.ethereum.org/EIPS/eip-165
+#[interface_id]
+pub trait IErc165 {
+    /// Returns true if this contract implements the interface defined by
+    /// `interfaceId`. See the corresponding [ERC section]
+    /// to learn more about how these ids are created.
+    ///
+    /// Method [`IErc165::supports_interface`] should be reexported with
+    /// `#[public]` macro manually like this:
+    ///
+    /// ```rust,ignore
+    /// #[public]
+    /// impl Erc20Example {
+    ///     fn supports_interface(interface_id: FixedBytes<4>) -> bool {
+    ///         Erc20::supports_interface(interface_id)
+    ///             || Erc20Metadata::supports_interface(interface_id)
+    ///     }
+    /// }
+    /// ```
+    ///
+    /// # Arguments
+    ///
+    /// * `interface_id` - The interface identifier, as specified in [ERC
+    ///   section]
+    ///
+    /// [ERC section]: https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified
+    fn supports_interface(interface_id: FixedBytes<4>) -> bool;
+}
+
+/// Implementation of the [`IErc165`] trait.
+///
+/// Contracts that want to support ERC-165 should implement the [`IErc165`]
+/// trait for the additional interface id that will be supported and call
+/// [`Erc165::supports_interface`] like:
+///
+/// ```rust,ignore
+/// impl IErc165 for Erc20 {
+///     fn supports_interface(interface_id: FixedBytes<4>) -> bool {
+///         crate::token::erc20::INTERFACE_ID == u32::from_be_bytes(*interface_id)
+///             || Erc165::supports_interface(interface_id)
+///     }
+/// }
+/// ```
+pub struct Erc165;
+
+impl IErc165 for Erc165 {
+    fn supports_interface(interface_id: FixedBytes<4>) -> bool {
+        Self::INTERFACE_ID == u32::from_be_bytes(*interface_id)
+    }
+}
diff --git a/contracts/src/utils/introspection/mod.rs b/contracts/src/utils/introspection/mod.rs
new file mode 100644
index 00000000..72077bf5
--- /dev/null
+++ b/contracts/src/utils/introspection/mod.rs
@@ -0,0 +1,2 @@
+//! Stylus contract's introspection helpers library.
+pub mod erc165;
diff --git a/contracts/src/utils/mod.rs b/contracts/src/utils/mod.rs
index 7c24bc20..b8f56cef 100644
--- a/contracts/src/utils/mod.rs
+++ b/contracts/src/utils/mod.rs
@@ -1,5 +1,6 @@
 //! Common Smart Contracts utilities.
 pub mod cryptography;
+pub mod introspection;
 pub mod math;
 pub mod metadata;
 pub mod nonces;
diff --git a/examples/erc20/src/lib.rs b/examples/erc20/src/lib.rs
index 8c732c6f..ace37b5f 100644
--- a/examples/erc20/src/lib.rs
+++ b/examples/erc20/src/lib.rs
@@ -9,7 +9,7 @@ use openzeppelin_stylus::{
         extensions::{capped, Capped, Erc20Metadata, IErc20Burnable},
         Erc20, IErc20,
     },
-    utils::Pausable,
+    utils::{introspection::erc165::IErc165, Pausable},
 };
 use stylus_sdk::prelude::{entrypoint, public, sol_storage};
 
@@ -106,11 +106,8 @@ impl Erc20Example {
         self.erc20.transfer_from(from, to, value).map_err(|e| e.into())
     }
 
-    fn supports_interface(
-        interface_id: FixedBytes<4>,
-    ) -> Result<bool, Vec<u8>> {
-        let interface_id = u32::from_be_bytes(*interface_id);
-        let supported = interface_id == <Erc20 as IErc20>::INTERFACE_ID;
-        Ok(supported)
+    fn supports_interface(interface_id: FixedBytes<4>) -> bool {
+        Erc20::supports_interface(interface_id)
+            || Erc20Metadata::supports_interface(interface_id)
     }
 }
diff --git a/examples/erc20/tests/erc20.rs b/examples/erc20/tests/erc20.rs
index e6595f00..68cb443c 100644
--- a/examples/erc20/tests/erc20.rs
+++ b/examples/erc20/tests/erc20.rs
@@ -1350,17 +1350,24 @@ async fn support_interface(alice: Account) -> Result<()> {
         .await?
         .address()?;
     let contract = Erc20::new(contract_addr, &alice.wallet);
-    let invalid_interface_id: u32 = 0x_ffffffff;
+    let invalid_interface_id: u32 = 0xffffffff;
     let Erc20::supportsInterfaceReturn {
         supportsInterface: supports_interface,
     } = contract.supportsInterface(invalid_interface_id.into()).call().await?;
 
     assert_eq!(supports_interface, false);
 
-    let valid_interface_id: u32 = 0x_36372b07;
+    let erc20_interface_id: u32 = 0x36372b07;
     let Erc20::supportsInterfaceReturn {
         supportsInterface: supports_interface,
-    } = contract.supportsInterface(valid_interface_id.into()).call().await?;
+    } = contract.supportsInterface(erc20_interface_id.into()).call().await?;
+
+    assert_eq!(supports_interface, true);
+
+    let erc165_interface_id: u32 = 0x01ffc9a7;
+    let Erc20::supportsInterfaceReturn {
+        supportsInterface: supports_interface,
+    } = contract.supportsInterface(erc165_interface_id.into()).call().await?;
 
     assert_eq!(supports_interface, true);
 
diff --git a/examples/erc721/src/lib.rs b/examples/erc721/src/lib.rs
index a707e070..3b1c22ef 100644
--- a/examples/erc721/src/lib.rs
+++ b/examples/erc721/src/lib.rs
@@ -9,7 +9,7 @@ use openzeppelin_stylus::{
         extensions::{Erc721Enumerable as Enumerable, IErc721Burnable},
         Erc721, IErc721,
     },
-    utils::Pausable,
+    utils::{introspection::erc165::IErc165, Pausable},
 };
 use stylus_sdk::{
     abi::Bytes,
@@ -152,11 +152,8 @@ impl Erc721Example {
         Ok(())
     }
 
-    fn supports_interface(
-        interface_id: FixedBytes<4>,
-    ) -> Result<bool, Vec<u8>> {
-        let interface_id = u32::from_be_bytes(*interface_id);
-        let supported = interface_id == <Erc721 as IErc721>::INTERFACE_ID;
-        Ok(supported)
+    pub fn supports_interface(interface_id: FixedBytes<4>) -> bool {
+        Erc721::supports_interface(interface_id)
+            || Enumerable::supports_interface(interface_id)
     }
 }
diff --git a/examples/erc721/tests/erc721.rs b/examples/erc721/tests/erc721.rs
index 357de749..cfc23d3d 100644
--- a/examples/erc721/tests/erc721.rs
+++ b/examples/erc721/tests/erc721.rs
@@ -2109,10 +2109,17 @@ async fn support_interface(alice: Account) -> eyre::Result<()> {
 
     assert_eq!(supports_interface, false);
 
-    let valid_interface_id: u32 = 0x_80ac58cd;
+    let erc721_interface_id: u32 = 0x80ac58cd;
     let Erc721::supportsInterfaceReturn {
         supportsInterface: supports_interface,
-    } = contract.supportsInterface(valid_interface_id.into()).call().await?;
+    } = contract.supportsInterface(erc721_interface_id.into()).call().await?;
+
+    assert_eq!(supports_interface, true);
+
+    let erc165_interface_id: u32 = 0x01ffc9a7;
+    let Erc721::supportsInterfaceReturn {
+        supportsInterface: supports_interface,
+    } = contract.supportsInterface(erc165_interface_id.into()).call().await?;
 
     assert_eq!(supports_interface, true);