The Ethiopian Highlands (also called the Abyssinian Highlands) is a rugged mass of mountains extending from Ethiopia to Eritrea in Northeast Africa. It forms the largest continuous area of its elevation in the continent, with little of its surface falling below 1,500 m (4,900 ft), while the summits reach heights of up to 4,550 m (14,930 ft). It is sometimes called the "Roof of Africa" due to its height and large area. Ethiopia is the only country in the region with such a high elevated surface. This elevated surface is bisected diagonally by the Great East African Rift System which extends from Syria to Mozambique across the East African Lakes. Most of the Ethiopian Highlands are part of central and northern Ethiopia, with the Eritrean Highlands as its northernmost portion. The Ethiopia-Yemen Continental Flood Basalts are shared between the Horn of Africa and highlands of Upper Yemen along with the cultural, historical, and genetic ties of the two regions on opposite ends of the Red Sea.

In the southern parts of the Ethiopian Highlands once was located the Kingdom of Kaffa, a medieval and early modern state, whence the coffee plant was exported to the Arabian Peninsula. The land of the former kingdom is mountainous with stretches of forest. The land is very fertile, capable of three harvests a year. The term coffee derives from the Arabic: قهوة (qahwah) and is traced to Kaffa.

In the Amhara region to the north, genetic adaptation (e.g., rs10803083, an SNP associated with the rate and function of hemoglobin; BHLHE41, a gene associated with circadian rhythm and hypoxia response; EGNL1, a gene strongly associated with oxygen homeostasis in mammals) to hypoxia and low atmospheric pressure has been found among the Amhara people, which may have developed within the past 5000 years.

The Highlands are divided into northwestern and southeastern portions by the Main Ethiopian Rift, which contains a number of salt lakes. The northwestern portion, known as the Abyssinian Massif, includes the Semien Mountains, part of which has been designated the Simien Mountains National Park. Its summit, Ras Dashen (4,550 m), is the highest peak in Ethiopia. Lake Tana, the source of the Blue Nile, also lies in the northwestern portion of the Ethiopian Highlands.

The southeastern portion is known as the Harar Massif. It's bounded in the west, by the fault line of the Rift Valley, in the east, by the Ogaden Lowlands and in the south, by the Elkerie and Borena Lowlands. Its highest peaks are located in the Bale Zone of Ethiopia's Oromia Region. The Bale Mountains, also designated a national park, are nearly as high as those of Semien. It is the main source of the Wabishebelle and Genalle (Juba). The range includes peaks of over 4,000 m. Among the former are Mount Tullu Demtu (4,337 m), which is the second-highest major independent mountain in Ethiopia, and Mount Batu (4,307 m).

Most of the country's major cities are located at elevations of around 2,000–2,500 m (6,600–8,200 ft) above sea level, including Addis Ababa, Ethiopia's capital and largest city, and historic capitals such as Gondar and Axum.

The Ethiopian Highlands began to rise 75 million years ago, as magma from the Earth's mantle uplifted a broad dome of the ancient rocks of the Arabian-Nubian Shield. The opening of the Great Rift Valley split the dome of the Ethiopian Highlands into three parts; the mountains of the southern Arabian Peninsula are geologically part of the ancient Ethiopian Highlands, separated by the rifting which created the Red Sea and Gulf of Aden and separated Africa from Arabia.

Around 30 million years ago, a flood basalt plateau began to form, piling layers upon layers of voluminous fissure-fed basaltic lava flows. Most of the flows were tholeiitic, save for a thin layer of alkali basalts and minor amounts of felsic (high-silica) volcanic rocks, such as rhyolite. In the waning stages of the flood basalt episode, large explosive caldera-forming eruptions also occurred.