diff --git a/crates/compiler/builtins/src/bitcode.rs b/crates/compiler/builtins/src/bitcode.rs
index f6733f7f4c..56d0bb339b 100644
--- a/crates/compiler/builtins/src/bitcode.rs
+++ b/crates/compiler/builtins/src/bitcode.rs
@@ -73,7 +73,6 @@ pub enum DecWidth {
 pub enum FloatWidth {
     F32,
     F64,
-    F128,
 }
 
 impl FloatWidth {
@@ -86,7 +85,6 @@ impl FloatWidth {
         match self {
             F32 => 4,
             F64 => 8,
-            F128 => 16,
         }
     }
 
@@ -99,7 +97,7 @@ impl FloatWidth {
         // the compiler is targeting (e.g. what the Roc code will be compiled to).
         match self {
             F32 => 4,
-            F64 | F128 => match target_info.architecture {
+            F64 => match target_info.architecture {
                 X86_64 | Aarch64 | Wasm32 => 8,
                 X86_32 | Aarch32 => 4,
             },
@@ -225,7 +223,6 @@ impl Index<FloatWidth> for IntrinsicName {
         match index {
             FloatWidth::F32 => self.options[1],
             FloatWidth::F64 => self.options[2],
-            FloatWidth::F128 => self.options[3],
         }
     }
 }
@@ -256,7 +253,6 @@ macro_rules! float_intrinsic {
 
         output.options[1] = concat!($name, ".f32");
         output.options[2] = concat!($name, ".f64");
-        output.options[3] = concat!($name, ".f128");
 
         output
     }};
diff --git a/crates/compiler/gen_llvm/src/llvm/build.rs b/crates/compiler/gen_llvm/src/llvm/build.rs
index 3bb3a7d19d..b82f7341e2 100644
--- a/crates/compiler/gen_llvm/src/llvm/build.rs
+++ b/crates/compiler/gen_llvm/src/llvm/build.rs
@@ -709,7 +709,6 @@ fn float_with_precision<'a, 'ctx, 'env>(
     match float_width {
         FloatWidth::F64 => env.context.f64_type().const_float(value).into(),
         FloatWidth::F32 => env.context.f32_type().const_float(value).into(),
-        FloatWidth::F128 => todo!("F128 is not implemented"),
     }
 }
 
@@ -3034,7 +3033,6 @@ fn build_switch_ir<'a, 'ctx, 'env>(
             let int_type = match float_width {
                 FloatWidth::F32 => env.context.i32_type(),
                 FloatWidth::F64 => env.context.i64_type(),
-                FloatWidth::F128 => env.context.i128_type(),
             };
 
             builder
diff --git a/crates/compiler/gen_llvm/src/llvm/compare.rs b/crates/compiler/gen_llvm/src/llvm/compare.rs
index a03fd0bb50..0cd94a6eb0 100644
--- a/crates/compiler/gen_llvm/src/llvm/compare.rs
+++ b/crates/compiler/gen_llvm/src/llvm/compare.rs
@@ -111,7 +111,6 @@ fn build_eq_builtin<'a, 'ctx, 'env>(
             use FloatWidth::*;
 
             let name = match float_width {
-                F128 => "eq_f128",
                 F64 => "eq_f64",
                 F32 => "eq_f32",
             };
@@ -276,7 +275,6 @@ fn build_neq_builtin<'a, 'ctx, 'env>(
             use FloatWidth::*;
 
             let name = match float_width {
-                F128 => "neq_f128",
                 F64 => "neq_f64",
                 F32 => "neq_f32",
             };
diff --git a/crates/compiler/gen_llvm/src/llvm/convert.rs b/crates/compiler/gen_llvm/src/llvm/convert.rs
index e752e98b43..1cbe255fed 100644
--- a/crates/compiler/gen_llvm/src/llvm/convert.rs
+++ b/crates/compiler/gen_llvm/src/llvm/convert.rs
@@ -202,7 +202,6 @@ pub fn float_type_from_float_width<'a, 'ctx, 'env>(
     use FloatWidth::*;
 
     match float_width {
-        F128 => todo!("F128 is not implemented"),
         F64 => env.context.f64_type(),
         F32 => env.context.f32_type(),
     }
diff --git a/crates/compiler/gen_llvm/src/llvm/intrinsics.rs b/crates/compiler/gen_llvm/src/llvm/intrinsics.rs
index dccd7e133e..94de9dfc5d 100644
--- a/crates/compiler/gen_llvm/src/llvm/intrinsics.rs
+++ b/crates/compiler/gen_llvm/src/llvm/intrinsics.rs
@@ -34,7 +34,6 @@ fn add_float_intrinsic<'ctx, F>(
 
     check!(FloatWidth::F32, ctx.f32_type());
     check!(FloatWidth::F64, ctx.f64_type());
-    // check!(IntWidth::F128, ctx.i128_type());
 }
 
 fn add_int_intrinsic<'ctx, F>(
diff --git a/crates/compiler/gen_llvm/src/llvm/lowlevel.rs b/crates/compiler/gen_llvm/src/llvm/lowlevel.rs
index d732b6ce1e..49cfca78d9 100644
--- a/crates/compiler/gen_llvm/src/llvm/lowlevel.rs
+++ b/crates/compiler/gen_llvm/src/llvm/lowlevel.rs
@@ -2124,13 +2124,6 @@ fn build_float_unary_op<'a, 'ctx, 'env>(
                     "f64_to_f32",
                 ),
                 (FloatWidth::F64, FloatWidth::F64) => arg.into(),
-                (FloatWidth::F128, FloatWidth::F128) => arg.into(),
-                (FloatWidth::F128, _) => {
-                    unimplemented!("I cannot handle F128 with Num.toFrac yet")
-                }
-                (_, FloatWidth::F128) => {
-                    unimplemented!("I cannot handle F128 with Num.toFrac yet")
-                }
             }
         }
         NumCeiling => {
diff --git a/crates/compiler/gen_wasm/src/layout.rs b/crates/compiler/gen_wasm/src/layout.rs
index 83c86265f1..44097b94f1 100644
--- a/crates/compiler/gen_wasm/src/layout.rs
+++ b/crates/compiler/gen_wasm/src/layout.rs
@@ -21,7 +21,6 @@ pub enum StackMemoryFormat {
     /// Record, Str, List, etc.
     DataStructure,
     Int128,
-    Float128,
     Decimal,
 }
 
@@ -71,11 +70,6 @@ impl WasmLayout {
                 match float_width {
                     F32 => Self::Primitive(ValueType::F32, size),
                     F64 => Self::Primitive(ValueType::F64, size),
-                    F128 => Self::StackMemory {
-                        size,
-                        alignment_bytes,
-                        format: StackMemoryFormat::Float128,
-                    },
                 }
             }
 
@@ -156,7 +150,7 @@ impl CallConv {
         use ValueType::*;
 
         match format {
-            Int128 | Float128 | Decimal => &[I64, I64],
+            Int128 | Decimal => &[I64, I64],
 
             DataStructure => {
                 if size == 0 {
@@ -191,7 +185,7 @@ impl CallConv {
         use StackMemoryFormat::*;
 
         match format {
-            Int128 | Float128 | Decimal => WriteToPointerArg,
+            Int128 | Decimal => WriteToPointerArg,
 
             DataStructure => {
                 if size == 0 {
diff --git a/crates/compiler/gen_wasm/src/low_level.rs b/crates/compiler/gen_wasm/src/low_level.rs
index 82efa09c8b..71417f1f0b 100644
--- a/crates/compiler/gen_wasm/src/low_level.rs
+++ b/crates/compiler/gen_wasm/src/low_level.rs
@@ -30,7 +30,6 @@ enum CodeGenNumType {
     F32,     // Supported in Wasm instruction set
     F64,     // Supported in Wasm instruction set
     I128,    // Bytes in memory, needs Zig builtins
-    F128,    // Bytes in memory, needs Zig builtins
     Decimal, // Bytes in memory, needs Zig builtins
 }
 
@@ -66,7 +65,6 @@ impl From<Layout<'_>> for CodeGenNumType {
                 Builtin::Float(float_width) => match float_width {
                     FloatWidth::F32 => F32,
                     FloatWidth::F64 => F64,
-                    FloatWidth::F128 => F128,
                 },
                 Builtin::Decimal => Decimal,
                 _ => not_num_error(),
@@ -91,7 +89,6 @@ impl From<StackMemoryFormat> for CodeGenNumType {
     fn from(format: StackMemoryFormat) -> CodeGenNumType {
         match format {
             StackMemoryFormat::Int128 => CodeGenNumType::I128,
-            StackMemoryFormat::Float128 => CodeGenNumType::F128,
             StackMemoryFormat::Decimal => CodeGenNumType::Decimal,
             StackMemoryFormat::DataStructure => {
                 internal_error!("Tried to perform a Num low-level operation on a data structure")
@@ -804,7 +801,6 @@ impl<'a> LowLevelCall<'a> {
                         self.load_args(backend);
                         backend.code_builder.f64_add()
                     }
-                    FloatWidth::F128 => todo!("Num.add for f128"),
                 },
                 Layout::Builtin(Builtin::Decimal) => {
                     self.load_args_and_call_zig(backend, bitcode::DEC_ADD_OR_PANIC)
@@ -841,7 +837,6 @@ impl<'a> LowLevelCall<'a> {
                         self.load_args(backend);
                         backend.code_builder.f64_add()
                     }
-                    FloatWidth::F128 => todo!("Num.add for f128"),
                 },
                 Layout::Builtin(Builtin::Decimal) => {
                     // TODO: don't panic
@@ -897,7 +892,6 @@ impl<'a> LowLevelCall<'a> {
                         self.load_args(backend);
                         backend.code_builder.f64_sub()
                     }
-                    FloatWidth::F128 => todo!("Num.sub for f128"),
                 },
                 Layout::Builtin(Builtin::Decimal) => {
                     self.load_args_and_call_zig(backend, bitcode::DEC_SUB_OR_PANIC)
@@ -934,7 +928,6 @@ impl<'a> LowLevelCall<'a> {
                         self.load_args(backend);
                         backend.code_builder.f64_sub()
                     }
-                    FloatWidth::F128 => todo!("Num.sub for f128"),
                 },
                 Layout::Builtin(Builtin::Decimal) => {
                     // TODO: don't panic
@@ -988,7 +981,6 @@ impl<'a> LowLevelCall<'a> {
                         self.load_args(backend);
                         backend.code_builder.f64_mul()
                     }
-                    FloatWidth::F128 => todo!("Num.mul for f128"),
                 },
                 Layout::Builtin(Builtin::Decimal) => {
                     self.load_args_and_call_zig(backend, bitcode::DEC_MUL_OR_PANIC)
@@ -1024,7 +1016,6 @@ impl<'a> LowLevelCall<'a> {
                         self.load_args(backend);
                         backend.code_builder.f64_mul()
                     }
-                    FloatWidth::F128 => todo!("Num.mul for f128"),
                 },
                 Layout::Builtin(Builtin::Decimal) => {
                     // TODO: don't panic
@@ -1466,9 +1457,6 @@ impl<'a> LowLevelCall<'a> {
                     Layout::Builtin(Builtin::Float(FloatWidth::F64)) => {
                         backend.code_builder.f64_sqrt()
                     }
-                    Layout::Builtin(Builtin::Float(FloatWidth::F128)) => {
-                        todo!("sqrt for f128")
-                    }
                     _ => panic_ret_type(),
                 }
             }
@@ -2004,8 +1992,6 @@ impl<'a> LowLevelCall<'a> {
 
             StackMemoryFormat::Int128 => Self::eq_num128_bytes(backend, locations),
 
-            StackMemoryFormat::Float128 => todo!("equality for f128"),
-
             StackMemoryFormat::DataStructure => {
                 internal_error!("Data structure equality is handled elsewhere")
             }
@@ -2052,7 +2038,6 @@ impl<'a> LowLevelCall<'a> {
                 FloatWidth::F64 => {
                     self.load_args_and_call_zig(backend, &bitcode::STR_FROM_FLOAT[width]);
                 }
-                FloatWidth::F128 => todo!("F128 to Str"),
             },
             Layout::Builtin(Builtin::Decimal) => {
                 self.load_args_and_call_zig(backend, bitcode::DEC_TO_STR)
@@ -2090,27 +2075,13 @@ fn num_is_finite(backend: &mut WasmBackend<'_>, argument: Symbol) {
                 }
             }
         }
-        StackMemory {
-            format, location, ..
-        } => {
-            let (local_id, offset) = location.local_and_offset(backend.storage.stack_frame_pointer);
-
+        StackMemory { format, .. } => {
             match format {
                 // Integers and fixed-point numbers are always finite. Just return True.
                 StackMemoryFormat::Int128 | StackMemoryFormat::Decimal => {
                     backend.code_builder.i32_const(1)
                 }
 
-                // f128 is not supported anywhere else but it's easy to support it here, so why not...
-                StackMemoryFormat::Float128 => {
-                    backend.code_builder.get_local(local_id);
-                    backend.code_builder.i64_load(Align::Bytes4, offset + 8);
-                    backend.code_builder.i64_const(0x7fff_0000_0000_0000);
-                    backend.code_builder.i64_and();
-                    backend.code_builder.i64_const(0x7fff_0000_0000_0000);
-                    backend.code_builder.i64_ne();
-                }
-
                 StackMemoryFormat::DataStructure => {
                     internal_error!("Tried to perform NumIsFinite on a data structure")
                 }
diff --git a/crates/compiler/gen_wasm/src/storage.rs b/crates/compiler/gen_wasm/src/storage.rs
index a2d0032397..85f248b7b8 100644
--- a/crates/compiler/gen_wasm/src/storage.rs
+++ b/crates/compiler/gen_wasm/src/storage.rs
@@ -252,7 +252,7 @@ impl<'a> Storage<'a> {
                         .extend_from_slice(CallConv::C.stack_memory_arg_types(size, format));
 
                     let location = match format {
-                        Int128 | Float128 | Decimal => {
+                        Int128 | Decimal => {
                             // passed as two i64's but stored in the stack frame
                             wide_number_args.push(local_index);
                             let loc =
diff --git a/crates/compiler/mono/src/layout.rs b/crates/compiler/mono/src/layout.rs
index b3a0d0f8f6..27d85c2e24 100644
--- a/crates/compiler/mono/src/layout.rs
+++ b/crates/compiler/mono/src/layout.rs
@@ -2890,7 +2890,6 @@ impl<'a> Builtin<'a> {
                 use FloatWidth::*;
 
                 match float_width {
-                    F128 => alloc.text("Float128"),
                     F64 => alloc.text("Float64"),
                     F32 => alloc.text("Float32"),
                 }
diff --git a/crates/glue/src/RocType.roc b/crates/glue/src/RocType.roc
index ff18cda46d..cbc6cffa22 100644
--- a/crates/glue/src/RocType.roc
+++ b/crates/glue/src/RocType.roc
@@ -91,7 +91,6 @@ RocNum : [
     U128,
     F32,
     F64,
-    F128,
     Dec,
 ]
 
@@ -153,4 +152,4 @@ RocTagUnion : [
         nonNullPayload: TypeId,
         whichTagIsNull: [FirstTagIsNull, SecondTagIsNull],
     },
-]
\ No newline at end of file
+]
diff --git a/crates/glue/src/glue.rs b/crates/glue/src/glue.rs
index a352ff820a..325ea22370 100644
--- a/crates/glue/src/glue.rs
+++ b/crates/glue/src/glue.rs
@@ -571,7 +571,6 @@ struct RocType_RocDict {
 #[repr(u8)]
 pub enum RocNum {
     Dec = 0,
-    F128 = 1,
     F32 = 2,
     F64 = 3,
     I128 = 4,
@@ -590,7 +589,6 @@ impl core::fmt::Debug for RocNum {
     fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         match self {
             Self::Dec => f.write_str("RocNum::Dec"),
-            Self::F128 => f.write_str("RocNum::F128"),
             Self::F32 => f.write_str("RocNum::F32"),
             Self::F64 => f.write_str("RocNum::F64"),
             Self::I128 => f.write_str("RocNum::I128"),
diff --git a/crates/glue/src/rust_glue.rs b/crates/glue/src/rust_glue.rs
index d00dfb8092..28b1ea1597 100644
--- a/crates/glue/src/rust_glue.rs
+++ b/crates/glue/src/rust_glue.rs
@@ -1737,7 +1737,6 @@ fn type_name(id: TypeId, types: &Types) -> String {
         RocType::Num(RocNum::I128) => "roc_std::I128".to_string(),
         RocType::Num(RocNum::F32) => "f32".to_string(),
         RocType::Num(RocNum::F64) => "f64".to_string(),
-        RocType::Num(RocNum::F128) => "roc_std::F128".to_string(),
         RocType::Num(RocNum::Dec) => "roc_std::RocDec".to_string(),
         RocType::RocDict(key_id, val_id) => format!(
             "roc_std::RocDict<{}, {}>",
@@ -2433,7 +2432,7 @@ fn has_float_help(roc_type: &RocType, types: &Types, do_not_recurse: &[TypeId])
             use RocNum::*;
 
             match num {
-                F32 | F64 | F128 => true,
+                F32 | F64 => true,
                 I8 | U8 | I16 | U16 | I32 | U32 | I64 | U64 | I128 | U128 | Dec => false,
             }
         }
diff --git a/crates/glue/src/types.rs b/crates/glue/src/types.rs
index 1504952789..fb93a78771 100644
--- a/crates/glue/src/types.rs
+++ b/crates/glue/src/types.rs
@@ -544,7 +544,6 @@ pub enum RocNum {
     U128,
     F32,
     F64,
-    F128,
     Dec,
 }
 
@@ -566,7 +565,6 @@ impl RocNum {
             RocNum::U128 => size_of::<roc_std::U128>(),
             RocNum::F32 => size_of::<f32>(),
             RocNum::F64 => size_of::<f64>(),
-            RocNum::F128 => todo!(),
             RocNum::Dec => size_of::<roc_std::RocDec>(),
         };
 
@@ -1083,11 +1081,6 @@ fn add_builtin_type<'a>(
                 RocType::Num(RocNum::F64),
                 layout,
             ),
-            F128 => types.add_anonymous(
-                &env.layout_cache.interner,
-                RocType::Num(RocNum::F128),
-                layout,
-            ),
         },
         (Builtin::Decimal, _) => types.add_anonymous(
             &env.layout_cache.interner,
diff --git a/crates/repl_eval/src/eval.rs b/crates/repl_eval/src/eval.rs
index 4f6031e2fc..3305b836b8 100644
--- a/crates/repl_eval/src/eval.rs
+++ b/crates/repl_eval/src/eval.rs
@@ -388,7 +388,6 @@ fn jit_to_ast_help<'a, A: ReplApp<'a>>(
             match float_width {
                 F32 => num_helper!(f32),
                 F64 => num_helper!(f64),
-                F128 => todo!("F128 not implemented"),
             }
         }
         Layout::Builtin(Builtin::Decimal) => num_helper!(RocDec),
@@ -590,7 +589,6 @@ fn addr_to_ast<'a, M: ReplAppMemory>(
             match float_width {
                 F32 => helper!(deref_f32, f32),
                 F64 => helper!(deref_f64, f64),
-                F128 => todo!("F128 not implemented"),
             }
         }
         (_, Layout::Builtin(Builtin::List(elem_layout))) => {