• J A Boland Group (Boland Motor Group)
• JD Sports Fashion Plc
• JD Sports Ireland
• JMK Group
• Jack & Jones

• Jackson's Hotel & Leisure Centre
• JacksonStone Recruitment
• Jacobs Engineering Group Inc
• Jigsaw – The National Centre for Youth Mental Health
• JobContax Recruitment Agency

• Joe Duffy Group
• John Paul Construction
• Johnson & Johnson
• Johnson Controls, Inc.
• Johnstown Garden Centre

• Join Talent
• Jones Engineering
• Jpmorgan Chase
• Jump Juice Bars Ltd
• Junction 14 Mayfield