diff --git a/include/PICA/shader.hpp b/include/PICA/shader.hpp
index f249cd0a..b1833607 100644
--- a/include/PICA/shader.hpp
+++ b/include/PICA/shader.hpp
@@ -23,6 +23,7 @@ namespace ShaderOpcodes {
 		RSQ = 0x0F,
 		MOVA = 0x12,
 		MOV = 0x13,
+		SLTI = 0x1B,
 		NOP = 0x21,
 		END = 0x22,
 		CALL = 0x24,
@@ -111,6 +112,7 @@ class PICAShader {
 	void mul(u32 instruction);
 	void rcp(u32 instruction);
 	void rsq(u32 instruction);
+	void slti(u32 instruction);
 
 	// src1, src2 and src3 have different negation & component swizzle bits in the operand descriptor
 	// https://problemkaputt.github.io/gbatek.htm#3dsgpushaderinstructionsetopcodesummary in the
diff --git a/src/core/PICA/shader_interpreter.cpp b/src/core/PICA/shader_interpreter.cpp
index de23d05c..4a7e0e70 100644
--- a/src/core/PICA/shader_interpreter.cpp
+++ b/src/core/PICA/shader_interpreter.cpp
@@ -36,6 +36,7 @@ void PICAShader::run() {
 			case ShaderOpcodes::NOP: break; // Do nothing
 			case ShaderOpcodes::RCP: rcp(instruction); break;
 			case ShaderOpcodes::RSQ: rsq(instruction); break;
+			case ShaderOpcodes::SLTI: slti(instruction); break;
 
 			case 0x30: case 0x31: case 0x32: case 0x33: case 0x34: case 0x35: case 0x36: case 0x37:
 				madi(instruction);
@@ -406,6 +407,27 @@ void PICAShader::madi(u32 instruction) {
 	}
 }
 
+void PICAShader::slti(u32 instruction) {
+	const u32 operandDescriptor = operandDescriptors[instruction & 0x1f];
+	const u32 src1 = (instruction >> 14) & 0x1f;
+	u32 src2 = (instruction >> 7) & 0x7f;
+	const u32 idx = (instruction >> 19) & 3;
+	const u32 dest = (instruction >> 21) & 0x1f;
+
+	src2 = getIndexedSource(src2, idx);
+
+	auto srcVec1 = getSourceSwizzled<1>(src1, operandDescriptor);
+	auto srcVec2 = getSourceSwizzled<2>(src2, operandDescriptor);
+	auto& destVector = getDest(dest);
+
+	u32 componentMask = operandDescriptor & 0xf;
+	for (int i = 0; i < 4; i++) {
+		if (componentMask & (1 << i)) {
+			destVector[3 - i] = srcVec1[3 - i] < srcVec2[3 - i] ? f24::fromFloat32(1.0) : f24::zero();
+		}
+	}
+}
+
 void PICAShader::cmp(u32 instruction) {
 	const u32 operandDescriptor = operandDescriptors[instruction & 0x7f];
 	const u32 src1 = (instruction >> 12) & 0x7f;