diff --git a/passes.go b/passes.go
new file mode 100644
index 0000000..5a1eefd
--- /dev/null
+++ b/passes.go
@@ -0,0 +1,101 @@
+package llvm
+
+/*
+#include "llvm-c/Transforms/PassBuilder.h"
+#include "llvm-c/Error.h"
+#include <stdlib.h>
+*/
+import "C"
+import (
+	"errors"
+	"unsafe"
+)
+
+type PassBuilderOptions struct {
+	C C.LLVMPassBuilderOptionsRef
+}
+
+// NewPassBuilderOptions creates a PassBuilderOptions which can be used
+// to specify pass options for RunPasses.
+func NewPassBuilderOptions() (pbo PassBuilderOptions) {
+	pbo.C = C.LLVMCreatePassBuilderOptions()
+	return
+}
+
+// RunPasses runs the specified optimization passes on the functions in the module.
+// `passes` is a comma separated list of pass names in the same format as llvm's
+// `opt -passes=...` command. Running `opt -print-passes` can list the available
+// passes.
+//
+// Some notable passes include:
+//
+//	default<O0>  -- run the default -O0 passes
+//	default<O1>  -- run the default -O1 passes
+//	default<O2>  -- run the default -O2 passes
+//	default<O3>  -- run the default -O3 passes
+//	default<Os>  -- run the default -Os passes, like -O2 but size concious
+//	default<Oz>  -- run the default -Oz passes, optimizing for size above all else
+func (mod Module) RunPasses(passes string, tm TargetMachine, options PassBuilderOptions) error {
+	cpasses := C.CString(passes)
+	defer C.free(unsafe.Pointer(cpasses))
+
+	err := C.LLVMRunPasses(mod.C, cpasses, tm.C, options.C)
+	if err != nil {
+		cstr := C.LLVMGetErrorMessage(err)
+		gstr := C.GoString(cstr)
+		C.LLVMDisposeErrorMessage(cstr)
+
+		return errors.New(gstr)
+	}
+	return nil
+}
+
+// SetVerifyEach toggles adding a VerifierPass to the PassBuilder,
+// ensuring all functions inside the module are valid.
+func (pbo PassBuilderOptions) SetVerifyEach(verifyEach bool) {
+	C.LLVMPassBuilderOptionsSetVerifyEach(pbo.C, boolToLLVMBool(verifyEach))
+}
+
+func (pbo PassBuilderOptions) SetDebugLogging(debugLogging bool) {
+	C.LLVMPassBuilderOptionsSetDebugLogging(pbo.C, boolToLLVMBool(debugLogging))
+}
+
+func (pbo PassBuilderOptions) SetLoopInterleaving(loopInterleaving bool) {
+	C.LLVMPassBuilderOptionsSetLoopInterleaving(pbo.C, boolToLLVMBool(loopInterleaving))
+}
+
+func (pbo PassBuilderOptions) SetLoopVectorization(loopVectorization bool) {
+	C.LLVMPassBuilderOptionsSetLoopVectorization(pbo.C, boolToLLVMBool(loopVectorization))
+}
+
+func (pbo PassBuilderOptions) SetSLPVectorization(slpVectorization bool) {
+	C.LLVMPassBuilderOptionsSetSLPVectorization(pbo.C, boolToLLVMBool(slpVectorization))
+}
+
+func (pbo PassBuilderOptions) SetLoopUnrolling(loopUnrolling bool) {
+	C.LLVMPassBuilderOptionsSetLoopUnrolling(pbo.C, boolToLLVMBool(loopUnrolling))
+}
+
+func (pbo PassBuilderOptions) SetForgetAllSCEVInLoopUnroll(forgetSCEV bool) {
+	C.LLVMPassBuilderOptionsSetForgetAllSCEVInLoopUnroll(pbo.C, boolToLLVMBool(forgetSCEV))
+}
+
+func (pbo PassBuilderOptions) SetLicmMssaOptCap(optCap uint) {
+	C.LLVMPassBuilderOptionsSetLicmMssaOptCap(pbo.C, C.unsigned(optCap))
+}
+
+func (pbo PassBuilderOptions) SetLicmMssaNoAccForPromotionCap(promotionCap uint) {
+	C.LLVMPassBuilderOptionsSetLicmMssaNoAccForPromotionCap(pbo.C, C.unsigned(promotionCap))
+}
+
+func (pbo PassBuilderOptions) SetCallGraphProfile(cgProfile bool) {
+	C.LLVMPassBuilderOptionsSetCallGraphProfile(pbo.C, boolToLLVMBool(cgProfile))
+}
+
+func (pbo PassBuilderOptions) SetMergeFunctions(mergeFuncs bool) {
+	C.LLVMPassBuilderOptionsSetMergeFunctions(pbo.C, boolToLLVMBool(mergeFuncs))
+}
+
+func (pbo PassBuilderOptions) Dispose() {
+	C.LLVMDisposePassBuilderOptions(pbo.C)
+}
diff --git a/passes_test.go b/passes_test.go
new file mode 100644
index 0000000..7fb9bf3
--- /dev/null
+++ b/passes_test.go
@@ -0,0 +1,80 @@
+package llvm
+
+import "testing"
+
+func TestPasses(t *testing.T) {
+	InitializeNativeTarget()
+	InitializeNativeAsmPrinter()
+
+	mod := NewModule("fac_module")
+
+	fac_args := []Type{Int32Type()}
+	fac_type := FunctionType(Int32Type(), fac_args, false)
+	fac := AddFunction(mod, "fac", fac_type)
+	fac.SetFunctionCallConv(CCallConv)
+	n := fac.Param(0)
+
+	entry := AddBasicBlock(fac, "entry")
+	iftrue := AddBasicBlock(fac, "iftrue")
+	iffalse := AddBasicBlock(fac, "iffalse")
+	end := AddBasicBlock(fac, "end")
+
+	builder := NewBuilder()
+	defer builder.Dispose()
+
+	builder.SetInsertPointAtEnd(entry)
+	If := builder.CreateICmp(IntEQ, n, ConstInt(Int32Type(), 0, false), "cmptmp")
+	builder.CreateCondBr(If, iftrue, iffalse)
+
+	builder.SetInsertPointAtEnd(iftrue)
+	res_iftrue := ConstInt(Int32Type(), 1, false)
+	builder.CreateBr(end)
+
+	builder.SetInsertPointAtEnd(iffalse)
+	n_minus := builder.CreateSub(n, ConstInt(Int32Type(), 1, false), "subtmp")
+	call_fac_args := []Value{n_minus}
+	call_fac := builder.CreateCall(fac_type, fac, call_fac_args, "calltmp")
+	res_iffalse := builder.CreateMul(n, call_fac, "multmp")
+	builder.CreateBr(end)
+
+	builder.SetInsertPointAtEnd(end)
+	res := builder.CreatePHI(Int32Type(), "result")
+	phi_vals := []Value{res_iftrue, res_iffalse}
+	phi_blocks := []BasicBlock{iftrue, iffalse}
+	res.AddIncoming(phi_vals, phi_blocks)
+	builder.CreateRet(res)
+
+	err := VerifyModule(mod, ReturnStatusAction)
+	if err != nil {
+		t.Errorf("Error verifying module: %s", err)
+		return
+	}
+
+	targ, err := GetTargetFromTriple(DefaultTargetTriple())
+	if err != nil {
+		t.Error(err)
+	}
+
+	mt := targ.CreateTargetMachine(DefaultTargetTriple(), "", "", CodeGenLevelDefault, RelocDefault, CodeModelDefault)
+
+	pbo := NewPassBuilderOptions()
+	defer pbo.Dispose()
+
+	t.Run("no error running default pass", func(t *testing.T) {
+		err := mod.RunPasses("default<Os>", mt, pbo)
+		if err != nil {
+			t.Error(err)
+		}
+	})
+
+	t.Run("errors on unknown pass name", func(t *testing.T) {
+		err := mod.RunPasses("badpassnamedoesnotexist", mt, pbo)
+		if err == nil {
+			t.Error("expecting error but got none")
+		}
+
+		if err.Error() != "unknown pass name 'badpassnamedoesnotexist'" {
+			t.Errorf("expected error about unknow pass name, instead got %s", err)
+		}
+	})
+}