The Sri Lanka Sinha Regiment (SLSR) stands as one of the most distinguished and respected infantry regiments of the Sri Lanka Army. Established on 1 October 1956 at the Imperial Camp, Diyatalawa, the Regiment was formed as the first rifle regiment of the Sri Lanka Army, marking a significant milestone in the nation's military history. The Regiment was initially raised with officers and soldiers drawn from the Ceylon Light Infantry, under the command of Lieutenant Colonel R.D. Jayatilleka, MBE, who became its first Commanding Officer.

On the same day, the volunteer counterpart of the Regiment was formed when the Rajarata Rifles was redesignated as the 2nd Volunteer Battalion of the Ceylon Sinha Regiment. The Regiment continued to expand with the establishment of the 3rd Volunteer Battalion at Nuwara Eliya on 1 October 1969. Following Sri Lanka's transition to a republic in 1972, the Ceylon Sinha Regiment was officially renamed the Sri Lanka Sinha Regiment.

During the 1980s, the rise of terrorism and threats to the nation's sovereignty led to a rapid expansion of the Sri Lanka Army. In response, the Sri Lanka Sinha Regiment grew significantly, raising numerous regular and volunteer battalions to meet the operational demands of the country. The Regiment played a vital role in safeguarding Sri Lanka's territorial integrity and became one of the largest and most battle-hardened infantry regiments in the Army.

A major milestone in the Regiment's history was the establishment of the Regimental Headquarters at Diyatalawa on 9 May 1988, at the very location where the Regiment was first raised in 1956. Brigadier D. Wijesinghe was appointed as the first Colonel Commandant. Later, on 21 October 1989, the Regimental Headquarters was relocated to Ambepussa, where it remains today as the Regimental Centre of the Sri Lanka Sinha Regiment.

Throughout its proud history, the Sri Lanka Sinha Regiment has demonstrated exceptional courage and professionalism in numerous military operations. The Regiment distinguished itself during major battles, including the defence of the Jaffna Fort and the historic Battle of Elephant Pass. Its members have earned some of the nation's highest military honors for gallantry, including recipients of the Parama Weera Vibhushanaya, Sri Lanka's highest award for valor.

Beyond military achievements, the Regiment has contributed significantly to peacekeeping operations, leadership development, sports, and community service. The Sri Lanka Sinha Regiment is also recognized for its unique rifle regiment traditions, discipline, and proud military heritage. Guided by its enduring motto, "Swift and Bold," the Regiment continues to uphold the highest standards of service, courage, and dedication to the nation.

Today, the legacy of the Sri Lanka Sinha Regiment lives on through its serving members and veterans, preserving a proud history of sacrifice, honor, and unwavering commitment to Sri Lanka.