This chapter discusses the surgical management of 6th nerve palsy. It emphasises the importance of determining whether the palsy is partial or complete as this defines both the surgical plan and the likely outcome. The use of diagnostic botulinum toxinBotulinum toxin can be helpful in determining lateral rectus function. If the palsy is partial then horizontal surgerySurgery on the rectus muscles should be undertaken, usually a recession of the medial rectus muscle and resection or plication of the lateral rectus muscle. If the palsy is complete a transposition procedureTransposition procedures will be required. The various transposition operations available are described. Second stage management for residual palsy or over correction is also discussed.